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1
Xu, Siyuan, Jie Liao und Kewei Fan. „Mechanism and Application of Soilbags Filled with Excavated Soil in Soft Soil Subgrade Treatment“. Applied Sciences 14, Nr. 5 (22.02.2024): 1806. http://dx.doi.org/10.3390/app14051806.
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This research addresses the characteristics of soft soil subgrades treated by soilbags filled with excavated clayey soil. We evaluated of the strength and deformation modulus of soilbags containing excavated soil using unconfined compression tests. In addition, the drainage consolidation characteristics of soilbag-treated subgrades were investigated via model consolidation tests. Furthermore, a practical application included the construction of a 100 m-long rural road subgrade with these soilbags. The field test and numerical simulation results included the surface settlement and pore water pressure during and after construction to validate the effectiveness of the soilbag treatment for soft soil subgrade. The results show that the soilbags significantly enhanced both the strength and deformation modulus of the soft soil, which met the design requirements after the soilbag treatment. The drainage attributes of the soilbag treatment were also found to support the consolidation process of the soft soil subgrade effectively. Notably, the pore water pressure diminished rapidly during the construction interval, which is beneficial to reducing the post-construction settlement. The settlement uniformity of the subgrade is good verification of the superiority of the soilbag-treated subgrades.
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Ma, Lijie, und Ying Kong. „Application Research of CFG Piles in the Treatment of Soft Soil Foundations for High-Speed Railways“. Academic Journal of Science and Technology 7, Nr. 1 (23.08.2023): 194–99. http://dx.doi.org/10.54097/ajst.v7i1.11368.
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In the construction of high-speed railways in our country, various complex terrains and geologies are often encountered. Therefore, the treatment of special subgrades, especially the reinforcement of soft soil subgrades, becomes extremely important. Currently, there are many methods for reinforcing weak and soft soil foundations, and during construction, appropriate and economical treatment methods should be selected based on the actual site conditions. This article intends to use the reinforcement treatment of the subgrade in the section from DK30+000 to +347.62 of the Ningbo-Hangzhou Passenger Dedicated Line as a basis to discuss the reinforcement of soft soil foundations and the application of CFG piles in soft soil foundations.
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Chaudhary, Braj Kishore, und Gopal Gautam. „Cost Comparison of Flexible Pavement on Weak Sub-Grade Soil Modified with Lime and SD“. SCITECH Nepal 17, Nr. 1 (13.12.2023): 64–71. http://dx.doi.org/10.3126/scitech.v17i1.60491.
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The effectiveness of flexible pavement is affected by the subgrade quality. The subgrade refers to a compacted layer of soil that provides sideways support to the pavement. When constructed on a weak subgrade, it negatively impacts the pavement's performance, leading to a shorter lifespan. Traditionally, the common method to stabilize a soft subgrade involves removing the weak soil and replacing it with stronger soil. However, due to the high expenses associated with soil replacement, highway agencies are exploring alternative approaches to constructing highways on soft subgrades. Soil stabilization is a commonly employed alternative in pavement construction, serving as an effective method to enhance the engineering characteristics of soil, including its strength and stability. This paper focuses on the utilization of lime and stone dust (SD) as admixtures for an efficient ground improvement technique over weak subgrade soil deposits. The California Bearing Ratio (CBR) test is conducted by making the specimens of weak subgrade by adding the variable percentages of a mixture of lime and SD. First, the soil was mixed up with lime to 12% by weight with an increment of 3% again the soil was mixed with SD with increments of 10% up to 50% by weight of soil. The study determined an optimal lime content of 3% based on the geotechnical properties of the mixture and the cost considerations of lime and the weak subgrade. Following this, SD was added to the optimized lime-weak subgrade mixture in varying increments of 10% by weight, up to a maximum of 40%. The modified mixes were then evaluated for their CBR and maximum dry density values. The CBR is increased to 15% and the total pavement thickness decreased to 725 mm for 50% SD addition with 4.89 % in cost reduction.
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Waruwu, Aazokhi, Paulus Dwi Surya Emili Yanto, Rika Deni Susanti und Syukurman Harefa. „Study bearing capacity of subgrade using combination bamboo grid and stabilized soil“. Journal of Infrastructure Planning and Engineering (JIPE) 1, Nr. 2 (25.10.2022): 87–92. http://dx.doi.org/10.22225/jipe.1.2.2022.87-92.
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The subgrade of road construction also determines the strength and resistance to loads on it. The subgrade in the field very varies from soft clay to hard soil. The subgrade of soft clay requires soil improvement to increase bearing capacity. This study aims to determine the increase in bearing capacity and modulus of subgrade reaction in stabilized soil with the bamboo grid. The research was conducted through a physical model using a test box. Soft clay is compacted and the above it is replaced with stabilized soil with and without the bamboo grid. The height of stabilized soil varied from 0-15 cm. The results showed that the bearing capacity increased along with the increase in height of stabilized soil. The subgrade of stabilized soil which was given additional reinforcement of bamboo grid was able to increase the value of bearing capacity and modulus of subgrade reaction. A significant increase was obtained in the height of stabilized soil at least equal to the diameter of the test plate.
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Tan, Feng, und Tai Quan Zhou. „Finite Element Analysis for Subgrade Consolidation Settlement in Soft Soil“. Applied Mechanics and Materials 448-453 (Oktober 2013): 1256–59. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.1256.
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The two-dimensional finite element model for subgrade consolidation settlement analysis within soft soil pile is developed using ABAQUS. The numerical simulation on a highway subgrade deformation is performed to study the variation of consolidation settlement and the excess pore water pressure distribution in the central location and the part under centerline of the embankment. The results show that settlement develops gradually with the increasing period of soil consolidation. The excess pore water pressure of deep subgrade soils under embankment centerline rise due to the increased load. After each soil layer was filled, the excess pore water pressure increased in the first and was stable later along with the increase of soil depth. After the embankment soil was filled completely, excess pore pressure dissipated with time developing until the completion of consolidation.
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Ashik, M. Mohamed. „Stabilization of Soft Subgrade Soil with Non-Woven Coir Geotextiles“. International journal of Emerging Trends in Science and Technology 04, Nr. 05 (23.05.2017): 5200–5202. http://dx.doi.org/10.18535/ijetst/v4i5.13.
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Liu, Song-Yu, Guang-Hua Cai, Guang-Yin Du, Liang Wang, Jiang-Shan Li und Xing-Chen Qian. „Field investigation of shallow soft-soil highway subgrade treated by mass carbonation technology“. Canadian Geotechnical Journal 58, Nr. 1 (Januar 2021): 97–113. http://dx.doi.org/10.1139/cgj-2020-0008.
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The innovative carbonation technique based on reactive MgO and CO2 has been identified as an environmentally friendly and efficient method in the improvement of weak soils. Previous laboratory studies have indicated that carbonated MgO-admixed soils had significant improvement in mechanical properties. However, there are to date limited investigations on the soft-soil field application of this technique. In this study, a field trial was conducted to ascertain the feasibility of the MgO mass carbonation technique in improving shallow soft-soil subgrades. A series of field tests, including temperature, dynamic cone penetrometer, and light-weight deflectometer tests, were undertaken. The results indicated that compared with uncarbonated soil layers, there was two to three times increase in dynamic resilient moduli and soil resistances of carbonated MgO-admixed soils. The outcomes of this field investigation will contribute to the utilization of the combined stabilizer of MgO and CO2 and the mass carbonation technology in subgrade improvement.
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Rochim, A., und L. Fitriyana. „Characterization of Subgrade Soil of Lowland Areas of Semarang City“. IOP Conference Series: Earth and Environmental Science 971, Nr. 1 (01.01.2022): 012034. http://dx.doi.org/10.1088/1755-1315/971/1/012034.
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Abstract The northern part of Semarang city has been suffering a lot from settlement and inundation caused by rainfall and tidal flood. The settlement is predicted to emerge from the subgrade soil containing soft soil with low bearing capacity and high compressibility. This study aims to characterize subgrade soil of lowland areas of Semarang city. In order to define the depth of soft soil, site class, soil classification, and the settlement, soil data was taken from twelve locations distributed in five sub districts of Semarang lowland areas. The minimum depth of subgrade soil is 30 m below the ground surface. To predict the settlement, subgrade soil was loaded by a surcharge load of 80 kPa, and a safety factor of 2 was taken into account. The analysis was based on N-SPT, cone resistance, index properties, and engineering properties. The result shows that the subgrade soil of Semarang lowland areas is dominated by soft clay with a depth of 5 m to 20 m with the site class from SE to SD. Soil is classified as CL and CH. The predicted settlement is from 0.321 m (lasts one year) to 1.395 m (lasts 13 years).
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Song, Bi Hong, Chun Ming Wang, Shu Guang Wang, Jian Hua Chen und Lu Ke. „Soft Soil Subgrade Vacuum Preloading Consolidation Deformation Analysis of Large Rigid Foundation“. Advanced Materials Research 1095 (März 2015): 556–60. http://dx.doi.org/10.4028/www.scientific.net/amr.1095.556.
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The large rigid foundation has a high requirement on subgrade consolidation deformation, especially the soft soil subgrade, of which the design and construction is very difficult. Through the analysis on subgrade treatment process of a sewage treatment plant in Zhejiang Province, this paper introduces the mathematical calculation model and the specific calculation method for treating the soft soil subgrade with the vacuum preloading method. The calculation results obtained has basically reflected the actual deformation process of the subgrade; it is a rational referential calculation method to guide the design and construction.
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Wang, Jiang, und Long Cai Yang. „Measures and Mechanism of Reinforcement of Soft Subgrade of High Speed Railway in Operation“. Applied Mechanics and Materials 353-356 (August 2013): 866–71. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.866.
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Some subgrade of high-speed railway in operation occurred abnormal settlement,so need to reinforcement, however, the reinforcement measures and these mechanism have got little attention. Numerical analysis method was adopted to study the mechanism and effects of the grounting and churning pile which was used to reinforce soft soil subgrade a high-speed railway Results shows that the settlement and lateral deformation not symmetrical distribution but got larger along the inclined derection of stratum, reinforcement by grouting can decrease the settlement and the transverse differential deformation by improving the properties of soil, which can decrease the viod ratio and increase the compression modulus; reinforcement by churning pile which can increase the stability of embankment on soft soil subgrade. The result could provide theoretical guidance for reinforcement of soft soil subgrade of high speed railway in operation.
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Hasriana, Lawalenna Samang, Tri Harianto und M. Natsir Djide. „Bearing capacity improvement of soft soil subgrade layer with Bio Stabilized Bacillus Subtilis“. MATEC Web of Conferences 181 (2018): 01001. http://dx.doi.org/10.1051/matecconf/201818101001.
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The problem that is often faced in a road construction is a soil subgrade (soft soil). If the subgrade has a low bearing capacity, causing the soil to decrease greatly, so the road construction will quickly be damaged. Method to overcome the problem is bio stabilization with bacteria utilization. The purpose of this research is to know the bearing capacity improvement of soft soil as subgrade layer with bacteria solution of bacillus subtilis. Tests include soil physical and mechanical properties, compaction parameters and CBR tests. This test is based on ASTM for each test. Variations in addition of bacterial solution were 2%, 4%, 6%, 8% and 10% of dry soil weight with 7 days curing time. The results showed that the maximum value of CBR of soft soil was found at 39% on 6% bacterial solution. Increased CBR value from 2.8% to 39% or 13 times than untreated soil. This shows the use of bacterial concentration solution on soft soil significantly increases the bearing capacity.
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Paneru, Harish, Mohan Prasad Acharya und Indra Prasad Acharya. „Cement Stabilization of soft soil subgrade and Cost Analysis“. Kathford Journal of Engineering and Management 2, Nr. 01 (31.12.2023): 1–16. http://dx.doi.org/10.3126/kjem.v2i01.61765.
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The soft soil when present in subgrade creates a lot of problem in highways. Due to soft soil subgrade, the rutting is predominant cause of flexible pavement failure all around the world. This kind of soil is either replaced or modified prior to construction of other layers of road to minimize the formation of rut. This study deals with stabilization of soft soil subgrade by cement. The sample was collected from a depth around existing road subgrade. A series of laboratory tests on untreated soil sample was first done to determine the competency of soil as a subgrade layer followed by preparation of sample with varying stabilizer content i.e. 4%, 6% and 8% cement by weight of dry soil, to determine the optimum stabilizer content. Samples with varying cement content were also prepared for California Bearing Ratio (hereafter, CBR) and Unconfined Compressive Strength (hereafter, UCS)with different curing periods i.e. 7 days for CBR and 3, 7, 14 and 28 days for UCS. UCS test on these sample showed a significant improvement over the values of natural soil without stabilizer. CBR showed a similar trend and the resulting modified soil was competent enough to be used as a subgrade for heavy traffic condition. The pavement was modelled using Kenpave for 30 and 50 million standard axle (msa) traffic intensity to determine the ideal pavement section for two types of pavement used in this study. In addition, the cost of construction for replacement method and for cement stabilization are determined using norms of Department of Road and District rate of Kathmandu and are compared. The cement stabilized soil with optimum content is found to be cheaper than conventional method of replacement.
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Yu, Shu Qiang, und Peng Ju Qin. „Strength and Deformation Analysis of the Double-Layer Subgrade by Finite Element Method“. Applied Mechanics and Materials 52-54 (März 2011): 1348–52. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.1348.
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In the area of alluvial soft soil, the double layer subgrade with rigid upper layer and soft lower layer is common. In such subgrade, the stress diffusion phenomena will occur under vertical load. In this paper, the stress and deformation of such subgrade are studied by ABAQUS. According to the calculation results, the plastic zone of subgrade appears in the upper layer soil of the interface, and then, it expands up and down the interface with the increase of load. The plastic zone expands rapidly in the lower layer soil. Finally, the subgrade gets up to its ultimate bearing capacity when the plastic zone reaches the foundation bottom. This results provides an effective analytical methods to the engineering designers. It has practical meaning.
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Jusi, U., P. Dhamrodji und H. Maizir. „Foam Mortar Layer in Soft Subgrade Embankment: A Review“. IOP Conference Series: Earth and Environmental Science 1321, Nr. 1 (01.04.2024): 012040. http://dx.doi.org/10.1088/1755-1315/1321/1/012040.
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Abstract Soils are the basis of the construction of civil engineering structures that are designed to support and withstand the weight of the structures above them. The main problems of soft soil include low bearing capacity and large settlement. In road pavements, the sub grade as the bottom layer of the road must have a good bearing capacity. Subgrade is a part that must be considered because of the weight of the pavement structure and the embankment above it. Soft soil conditions cause the need for reinforcement of the sub grade layer. Solving the problem of road construction is done by engineering so that the sub grade as the bottom layer of the road is safe and stable and has a good bearing capacity. The effort made to increase the bearing capacity of the subgrade is by reinforcing the soil (soil improvement). One of them is with lightweight material mortar-foam is an alternative construction material in soil reinforcement for road construction. Mortar-foam is formed from a mixture of foam, cement, sand and water. Research on foam mortars has been conducted in various places and countries in various ways and methods. This article will discuss the latest developments in the use of foam mortars as backfill in soft soils in the subgrade layer presented based on information provided by the author.
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Zhang, Ming, Nan-nan Li und Min Yang. „THE MULTI-FACTOR CONTROL AND EVALUATION OF HIGHWAY SOFT SOIL SUBGRADE STABILITY“. Stavební obzor - Civil Engineering Journal 31, Nr. 3 (30.10.2022): 427–43. http://dx.doi.org/10.14311/cej.2022.03.0032.
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When the surcharge preloading method is used in the treatment of soft soil subgrade, it is necessary to squeeze for more preloading drainage consolidation time under the premise of controlling the subgrade stability during the filling period. Considering the mutation of each monitoring indices and their interrelation when instability occurs in the fill subgrade, the inflection point analysis method through monitoring indices to control the subgrade stability comprehensively was proposed in this paper. The thin-layer rotary adding method was used to determine the ultimate filling depth and the loading plan for the highway soft soil subgrade during the filling period, with the inflection point analysis method in analyzing and evaluating the subgrade stability. The results showed that: (1) The ultimate fill height of the subgrade sections was obtained from the stability analysis results on the basis of the three indices of pore water pressure increment, settlement and lateral displacement, which was close to the prediction results of the thin-layer rotary adding method. (2) The stability control standard of the subgrade construction in the filling method was that the single-stage pore pressure coefficient should be within 1.2. (3) The subgrade stability control standard contained the maximum settlement rate of 20mm/d and the maximum lateral displacement rate of 3mm/d. (4) The geotextile setting in the highway subgrade effectively improved the ultimate bearing capacity of the subgrade, reduced the lateral displacement, improved the anti-slip stability, and increased the ultimate filling height and filling rate.
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Yang, Liang, Wenyuan Xu und Keke Li. „Analysis of the Embankment Settlement on Soft Soil Subgrade with a Cement Mixed Pile“. Advances in Civil Engineering 2021 (28.11.2021): 1–15. http://dx.doi.org/10.1155/2021/9949720.
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The settlement of the widening of soft soil subgrade highways is typically associated with different treatment positions of cement mixed piles. In order to overcome this, in the current paper we employ the finite element method to simulate and analyze the influence of piles under an existing road slope and under an existing subgrade and new embankment on the settlement characteristics of the subgrade and foundation. In particular, we focus on the influence of the pile length and pile spacing on the subgrade and foundation settlements based on a northern high-speed reconstruction and expansion project. The subgrade and foundation soils in the finite element analysis are considered to be homogeneous, continuous, and isotropic elastoplastic materials. The Mohr–Coulomb ideal elastoplastic constitutive model is implemented as the constitutive soil model. The impact of piles under an existing subgrade and new embankment on the settlement is observed to be more significant than that of piles under the existing road slope. Moreover, the subgrade and foundation settlements increase with the pile spacing under the existing road slope and under the existing subgrade and new embankment. More specifically, an increase of the pile spacing from 200% to 400% of the pile diameter is associated with an increase in the maximum settlement of the foundation surface from 1.76 to 1.85 cm (existing road slope) and from 1.44 to 1.96 cm (existing subgrade and new embankment). In addition, the subgrade and foundation settlements decrease for increasing pile lengths under the existing road slope and under the existing subgrade and new embankment, the pile length increases from 4.7 to 9.2 m, and the maximum foundation surface settlement is reduced from 6.2 to 5.52 cm and from 9.73 to 5.43 cm, respectively. The results can provide reference for future subgrade widening projects.
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Yang, Tan Shu, Yang Qu Tan und Cui Juan Luo. „Application of Pine Piles for Strengthening High Slope Channel Retaining Walls on Soft Soil Subgrade“. Applied Mechanics and Materials 438-439 (Oktober 2013): 1190–94. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.1190.
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In the modification of narrow deep soil channels of early urban excavation, because of great depth and steep slope, the gravity retaining wall slope will be needed. The problems of soft soil subgrade treatment at channel bottom have to be solved. Combined with the old channel treatment project of a city, as practical example, the method by which the soft subgrade of channel retaining walls strengthening with pine piles, is described. By application of Coulomb Theory, the stability calculation for gravity pitch-up oblique retaining walls is conducted. The results show that using pine piles is a good method for strengthening the soft soil subgrade with small thickness below the water level.
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Puppala, Anand J., Louay N. Mohammad und Aaron Allen. „Engineering Behavior of Lime-Treated Louisiana Subgrade Soil“. Transportation Research Record: Journal of the Transportation Research Board 1546, Nr. 1 (Januar 1996): 24–31. http://dx.doi.org/10.1177/0361198196154600103.
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Lime stabilization is often used to treat subgrade soils when they are soft and cohesive in nature. A study was conducted to investigate the engineering behavior, including the resilient and strength behaviors, of a lime-treated subgrade soil. The lime treatment procedure was adapted from the specifications of the Louisiana Department of Transportation and Development. Silty clay, a soil often found in Louisiana subgrades, is used as a base soil. A summary of various engineering properties of a lime-treated soil from resilient modulus, unconfined compression strength, and California bearing ratio (CBR) tests conducted at five moisture content and dry density levels is provided. Tests were also performed on the raw soil without lime treatment, and these results were compared with those of tests with the lime-treated soil. The comparisons indicate that the present lime treatment method results in an increase in strength and resilient modulus properties and a decrease in plasticity characteristics and plastic strains. A regression model with three constants was used to analyze the resilient modulus test results. The model constants are presented as functions of soil properties. Resilient modulus correlations that use either CBR or unconfined compression strength, moisture content, dry density, degree of compaction, and stresses as dependent attributes are developed.
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Xiong, Feng, Xuebin Wang, Fan Yang, Jiaqiang Yang, Li Hu und Rui Li. „Analytical and Numerical Study on the Stability of Highway Subgrade with Embedded Loading Berm in Soft Soil Area“. Applied Sciences 12, Nr. 23 (05.12.2022): 12440. http://dx.doi.org/10.3390/app122312440.
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Loading berm is an effective method for improving highway subgrade stability in soft soil areas. However, this method requires lots of construction space. It is not applicable in some areas with narrow construction spaces. To address this problem, an embedded loading berm (ELB) is proposed to improve highway subgrade stability, and the effects of ELB on the stability of the highway subgrade were investigated by analytical and numerical methods. Firstly, an analytical model was proposed to analyze the relationship between the ELB dimensions and subgrade stability factors. Then, numerical simulations were carried out to further reveal the stability factor of an actual subgrade with different ELBs. Lastly, ELB parameters’ sensitivity to the ELB stability factors was studied. The results show that the stability of the highway subgrade in soft soil areas can be significantly improved by the proposed ELB. With the loading berm width and height increasing, the subgrade stability factors can increase. The stability factors’ increase ratio with the increased ELB width is greater than that with the increased ELB height. The ELB parameter sensitivity order on the subgrade stability is as follows: width > height > density > cohesion > internal friction. In the design process, the ELB width and height can be mainly focused on. The research is significant for promoting the application of ELB in soft soil areas.
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Sahrul R., Mohammad. „Numerical Modeling of Soil Embankment on Soft Soil Using Variation of Expanded Polystyrene (EPS) Geofoam Material Type“. Sustainable Civil Building Management and Engineering Journal 1, Nr. 4 (05.07.2024): 8. http://dx.doi.org/10.47134/scbmej.v1i4.2871.
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Subgrade is the layer of soil that lies beneath the pavement. The subgrade plays an important role in supporting and spreading the load from the pavement to the underlying soil. Terzaghi, et al. (1967) state that soft soils can pose serious challenges in geotechnical engineering, due to their tendency to experience large settlement under structural loads. Handling soft soils often requires specialized methods such as preloading, vacuum consolidation, or the use of geosynthetics to improve stability. One of the geosynthetics used in handling soft soil is Expanded Polystyrene (EPS) Geofoam. This research aims to determine the settlement behavior of soil embankment on soft soil reinforced with EPS geofoam. The settlement behavior was obtained with the help of GeoStudio software. EPS geofoam has been used since 1960, this material weighs about 1% of the soil weight and less than 10% of the weight of other embankment materials. As a lightweight embankment material, EPS geofoam can reduce the load imposed on the embankment structure. Modeling of soil embankment on soft soil using various types of EPS geofoam material in this research uses GeoStudio software. The modeling analysis uses SIGMA/W in GeoStudio. Numerical modeling of variations in the type of EPS geofoam material in the embankment on soft soil gives the results of a decrease that is not too significant. The settlement results from modeling with GeoStudio are 0.33240 m for EPS 22, 0.33264 m for EPS 29, 0.33323 mm for EPS 39. EPS 39 provides 0.25% higher settlement than EPS 22.
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Lin, Yang, und Ya Bo He. „Key Construction Technology for Highway on Soft Foundation“. Advanced Materials Research 243-249 (Mai 2011): 6113–17. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.6113.
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In recent years, a lot of research practices have been done on improving the quality of subgrade construction and solving the differential settlement of subgrade. Therefore, key construction technology for highway on soft foundation is very important. This paper analysis common engineering problems on soft foundation and the development status for soft soil treatment technology, then build up the technology trends on it.
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Dea Pratiw, Selly, und Isdaryanto Iskandar. „SOIL SUBSTANCE ANALYSIS USING PVD WITH VACUUM CONSOLIDATION METHOD (VCM)“. International Journal of Engineering Applied Sciences and Technology 7, Nr. 5 (01.09.2022): 57–66. http://dx.doi.org/10.33564/ijeast.2022.v07i05.010.
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The construction of toll roads on soft clay has the main problems of the relatively low bearing capacity of the subgrade and the relatively large and long duration of subgrade compression. The infrastructure built on the subgrade could be damaged before it reaches its planned age if the subgrade not repaired first. The selection of the soft clay soil handling method considers the cost and time at the time of construction in the field. For this reason, alternative methods needed that are cost and time efficient and have minimal risk to environmental impacts. The vacuum consolidation method (VCM) is an alternative to improve water saturated soft clay. Soil improvement using the vacuum consolidation method is intended to accelerate the settlement and increase the bearing capacity of the soft native soil by vacuum pumping the soil to reduce the moisture content and air content of the soil grains to accelerate long-term settlement and differential settlement. This study aimed to analyze the soil settlement using PVD with the vacuum consolidation method (VCM). The analysis conducted showed that to achieve 90% consolidation without PVD, it would take 13,922 years and using PVD, it would take 18 months, and using PVD and the vacuum consolidation method (VCM), it would take 4,8 months. The use of PVD with the vacuum consolidation method (VCM) can speed up the consolidation process compared to using PVD or only using PVD. The total decrease that occurred was 2,043 m.
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Chhetri, Sagar, und Plaban Deb. „Finite Element Analysis of Geogrid-Incorporated Flexible Pavement with Soft Subgrade“. Applied Sciences 14, Nr. 13 (03.07.2024): 5798. http://dx.doi.org/10.3390/app14135798.
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Improving the durability of flexible pavements and constructing new roads on weak soil foundations present significant challenges, prompting designers to explore alternative methods to prolong pavement lifespan. Geosynthetics have emerged as a promising solution for soil stabilization, with various materials developed for this purpose. The current study concentrates on using the finite element (FE) method to examine the effectiveness of geogrid-incorporated flexible pavements on soft soil substrates. A three-dimensional layered pavement is constructed with an FE model, incorporating subgrade layers of varying strengths based on their California bearing ratio (CBR) values, with a geogrid layer implemented to enhance subgrade stability. Additionally, attention is also given to investigating the effect of base course thickness. The findings reveal that the geogrid layer primarily influences the formation of plastic strains in the subgrade rather than resilient strains, effectively reducing vertical compressive strain by approximately 40%. With increasing CBR values, there is a reduction in vertical strain, although the influence zone extends up to a depth of 300 mm within the subgrade. At the surface of the subgrade, vertical strain decreases by around 17%, 39%, and 49% as the CBR values increase from 1% to 3%, 5%, and 8%, respectively.
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Liu, Yan Yan, Tian Qing Ling und Zhong Wen Huang. „Mechanism Analysis of GSPS System Strengthening Soft Base“. Advanced Materials Research 243-249 (Mai 2011): 4248–52. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4248.
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This paper analyzes the mechanism of geogrid-broken stone pile reinforced sand-gravel cushion soft base strengthening system (GSPS) using finite element based on the substantial project of a expressway in Sichuan province. The calculation results indicate that the GSPS system can significantly improve the vertical displacement (settlement) of subgrade with the vertical displacement around pile decreasing around 15%, and the subgrade displacement tends to be more uniform and smooth. Also, the GSPS system improves the horizontal displacement of subgrade the most compared with the common broken stone-pile, sand cushion and reinforced cushion. The embankment becomes relatively light when it is low, and the main top loads are borne by geogrid-broken stone piles. With the top loads increasing, the loads shift to the soil among piles, and the pile-soil stress ratio increases with the increase of stress level. The test and analysis results show that the value range of pile-soil stress ratio is 1.88~3.40.
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Pang, Chuan Qin. „Highway Slope Stability Analysis Based on Strength Decrease of the Subgrade“. Applied Mechanics and Materials 90-93 (September 2011): 3166–72. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.3166.
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In long-term operation process, highway subgrade is subjected to strength decrease easily，and the water environment around often causes the side slope side-slipping. In allusion to the common clay, massive indoor triaxial tests have been carried on, the relationship between the shear strength index and the water content, compactness of the compaction clay has been determined. Based on the above research, slope stability analysis software GEO-SLOPE is used, to analyze common earth fill subgrade, soft soil ground, mountainous area subgrade and earthquake area subgrade separately. The impact of subgrade strength decrease on the slope stability has been studied considering different subgrade filling height. The results indicate that no matter what kind of subgrade form, strength decrease of the subgrade causes highway slope safety coefficient to reduce, this especially obvious in the high subgrade condition. Partial jitter possibly happens when strength decrease of the subgrade achieves to above 80% of the common earth fill subgrade. The subgrade side-slipping possibly happens when strength decrease of the subgrade achieves to 50% of the soft soil subgrade. The subgrade safety coefficient decreases the most when the main performance is side-slipping jitter of the intersection between fills and digs of the mountainous area part-cut and part-fill subgrade. The subgrade jitter happens when the shear strength index decreases to 50% under the combination of strength decrease and seismic force of the earthquake area subgrade. The high subgrade and the maintenance management of the special road section should be strengthened to avoid the project disaster.
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Sorsa, Alemineh, Sanjaya Senadheera und Yoseph Birru. „Engineering Characterization of Subgrade Soils of Jimma Town, Ethiopia, for Roadway Design“. Geosciences 10, Nr. 3 (01.03.2020): 94. http://dx.doi.org/10.3390/geosciences10030094.
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Soils are naturally occurring materials that carry loads of civil engineering structures including roads and buildings. However, not all natural soils are suitable for such uses due to limited strength and instability under varying environmental conditions. A lack of adequate geotechnical investigations and soil characterization can result in the over-design of foundations, unexpected excavations to remove unsuitable soils, cost overruns, construction delays; and, contract disputes. In this research, an experimental plan was executed to determine the engineering properties of subgrade soil in Jimma Town in southwestern Ethiopia by using both disturbed and undisturbed soil samples. The plan included tests to determine the moisture content, specific gravity, grain-size analysis, Atterberg limits, compaction-density relationship, California Bearing Ratio (CBR), unconfined compression strength, and triaxial shear strength. X-ray diffraction (XRD) analysis was also conducted to determine the chemical composition of the soil. The soil characterization indicated that soft clay is the predominant subgrade soil type and that it has a very low load-bearing capacity, high plasticity, low strength and, high compressibility, which makes the soil unsuitable to serve as a highway subgrade without the help of soil improvement techniques.
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Song, Xiu Guang, Yi Fan Yu, Hong Bo Zhang, Hong Chao Li, Jian Qing Wu und Chao Li. „Study on New Technology of Treatment of Capillary Water in Subgrade with Soft Permeable Pipe Filled with Sand“. Advanced Materials Research 1051 (Oktober 2014): 692–95. http://dx.doi.org/10.4028/www.scientific.net/amr.1051.692.
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The technique took into account the high underground water level silty soil with stronger capillarity, subgrade soil easy water softened in Yellow River flood plain areas. It seriously affected the stability of subgrade. If lay a layer of gravel cushion in the ground, and then buried soft permeable pipes in the lower part of embankment, the permeable pipes filled with sand, the top of pipes sealed with geotextile, it would form the vertical drainage channel for the capillary water. So capillary water would along the vertical drainage channels formed by sand core soft permeable pipe and horizontal drainage channels formed by gravel cushion flowed out of the subgrade. The reliability of the method is verified by seep/w module in GEO-studio. This technique could effectively improve the strength and stability of subgrade, reduce the adverse effects of capillary water on the roadbed.
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Iskandar, Dedi, Elsa Eka Putri, Abdul Hakam und Arniza Fitri. „Effectiveness Of Portland Cement Type 1 In Stabilizing Soft Clay Soil As Subgrade For Road Construction“. Jurnal Rekayasa Sipil (JRS-Unand) 19, Nr. 1 (31.03.2023): 44. http://dx.doi.org/10.25077/jrs.19.1.44-53.2023.
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Sawah Lunto – Talawi road segment (STA 139 + 700 m) in Sawah Lunto city, West Sumatera province has sustained major damages and been the scene of several accidents since the past few years. The degression of soft clay subgrade, which has a limited bearing capacity and makes it structurally impractical to sustain road construction, was discovered to be the source of these damages. As a recent option for enhancing soil qualities, soil stabilization by employing a variety of pozzolanic and industrial materials has gained popularity. The objective of this study is to investigate the effectiveness of Portland cement type 1 as stabilizing material in improving the soil properties and carrying capacity requirements for soft clay soil used as subgrade in road construction. To accomplish the objectives of this study, a laboratory testing procedure was implemented. Unconfined Compressive Strength (USC) values on natural soil and treated soil with Portland cement type 1 admixture were measured and compared during laboratory experiments. Soft clay soils were stabilized with varying percentages of Portland cement type 1 with the proportions of approximately 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 10% by dry weight of soil during a 7-days curing period. Laboratory testing were performed in compliance with Indonesian National Standard (SNI): SNI 3420-2008 for testing Unconfined Compressive Strength. According to the results of laboratory testing, the UCS values increased roughly from 0.634 kg/cm2 (undisturbed natural soil) to 2.832 kg/cm2 (treated soil) by adding 3% of Portland cement type 1, and up to 8,024 kg/cm2 (treated soil) by adding 10% of Portland cement type 1. Based on the findings, it can be demonstrated that Portland cement type 1 can enhance clay soil's properties used as a subgrade for road construction, can create more stable road conditions, and can ultimately meet the technical feasibility requirements for the subgrade carrying capacity, particularly at the Sawah Lunto - Talawi road segment (STA 139 + 700 m).
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DJELLALI, Adel, Debojit SARKER, Ala HOUAM und Zoubir AOULMI. „BEHAVIOR OF AIRPORT FLEXIBLE PAVEMENT OVER SWELLING SOIL REINFORCED BY NEW ASPHALT LAYERS“. MINAR International Journal of Applied Sciences and Technology 05, Nr. 03 (01.09.2023): 155–63. http://dx.doi.org/10.47832/2717-8234.16.11.
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Longitudinal fractures are a common occurrence in runway pavements built on expansive soil subgrades. Such soil behavior leads to a reduction in the carrying capacity and lifespan of runways, as variations in water content accelerate cracking and deformations in the various pavement construction layers. To examine the behavior of reinforced runway flexible pavement over expanding subgrade soil, this study uses experimental and numerical analyses. Non-destructive deflection test is used to assess static behavior, measuring deformations and stresses in various runway profiles both before and after reinforcing with new asphalt layers created using the ACN-PCN process. Using the software program PLAXIS 3D, a three-dimensional (3D) finite element model (FEM) was designed to anticipate pavement distortions resulting from sudden, high-pressure movements caused by the expansion of soil. The materials were simulated using a soft-soil model (SSM) for the expanding subgrade and nonlinear behavior for the pavement layers. The experimental results and computer analyses were compared, and it was discovered that the measured and calculated deflection curves generally match very well
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Mittal, Ayush, und Shalinee Shukla. „Influence of Geotextile and Geogrid Reinforcement on Strength Behaviour of Soft Silty Soil“. Applied Mechanics and Materials 877 (Februar 2018): 264–69. http://dx.doi.org/10.4028/www.scientific.net/amm.877.264.
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Roads are the most important component for the economic and social development of any country. India has a total road network of more than 6 million kilometers, which carry around 90% of passenger traffic and 65% of freight traffic. More than 20% land area of India is covered with soils having low California bearing ratio (CBR) and shear strength values. The pavement constructed over such soils will lead to rapid increase in construction and maintenance costs. This study presents a laboratory investigation about the combined effect of geotextile and geogrid reinforcement, placed in layers at various depths from top of specimen, on the strength behaviour of poor subgrade soil. Heavy compaction, soaked CBR and unconfined compressive strength (UCS) tests are conducted. The test results indicate significant improvement in CBR and UCS values for all geosynthetic reinforced cases, whereas ductility and rupture strength remains almost constant as compared to virgin soil. Scanning electron microscopy (SEM) analysis shows significant bonding between soil particles and fibers of geogrid, causing stress transfer from soil to reinforcing material and hence preventing soil from overstressing. It is concluded that combination of geogrid and geotextile can be used effectively for reinforcing poor subgrade soil.
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Ma, Yong, Mao Tian Luan und Zhong Chang Wang. „Experimental Study on Dynamic Compaction-Plastics Drain Board Method in Backfill Subgrade Reinforcement“. Key Engineering Materials 474-476 (April 2011): 2032–36. http://dx.doi.org/10.4028/www.scientific.net/kem.474-476.2032.
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Plastics drain board method is one of the most effective ways of reducing excess pore water pressure during the process of dynamic compaction in soft soil subgrade reinforcement. Based on field test in neritic backfilled area of Jinzhou Port 207B berth, the pore water pressure, groundwater level, subgrade bearing capacity and time effect of deformation have been measured and analyzed. The application of dynamic compaction-PDB method makes a mighty advance of the dynamic compaction method, which provides a new way for soft soil treatment in coastal areas.
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Anggraini, M., P. Dhamrodji und H. Maizir. „Geofoam Block in Soft Soil Embankment Applications: A Review“. IOP Conference Series: Earth and Environmental Science 1321, Nr. 1 (01.04.2024): 012019. http://dx.doi.org/10.1088/1755-1315/1321/1/012019.
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Abstract The major issues of building a road over soft soils are low bearing capacity and large settlements. The challenges of road construction on soft soils are enormous, so innovative and environmentally friendly methods are required. Geofoam is a type of lightweight infill material and was already used in Norway in road construction applications in 1972. Using Geofoam reduces compacted fill by 40%, less excavation required and less pulverization of native soil making this a time-saving and economically and environmentally viable solution. The purpose of Geofoam backfill is for lightweight backfilling, reducing soil pressure. Geofoam blocks can be used as a substitute for soft soil fill or as fill on top of soft soil as subgrade for pavement. This paper discusses the latest developments on the various applications of Geofoam blocks as backfill in soft soils presented based on information provided by the author.
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Omowumi, Ademila. „GEOTECHNICAL INFLUENCE OF UNDERLYING SOILS TO PAVEMENT FAILURE IN SOUTHWESTERN PART OF NIGERIA“. Malaysian Journal of Sustainable Environment 4, Nr. 1 (30.09.2018): 19. http://dx.doi.org/10.24191/myse.v4i1.5604.
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Roads in Nigeria are usually constructed without in-depth knowledge of the subsoil that serves as the foundation for the road elements. Road failures are often associated to poor construction materials or inadequate design without cognisance of the underlying soils. Engineering properties of ten bulk soil samples collected from the subgrade of Arigidi/Oke-Agbe highway were investigated to determine their suitability for highway pavement. Results show that all the subgrade soils below the failed locations have higher plasticity indices, which is an indication of their high swelling potential, and they are classified as A-7-6 clayey soils with high-water adsorption capability (16.1 – 22.4%) compared to subgrade soils from the stable locations. Low compacted density (1325 – 1928 Kg/m3), extremely poor CBR values; 8 – 31% (unsoaked) and 3 – 8% (soaked) which indicate percentage reduction in strength of the soils up to 77% on exposure to excessive moisture and the predominance of fines (> 59%) in the soils are responsible for the degree of instability. Furthermore, soft to low stiffness (49 – 131 kN/m2) and poor permeability of the subgrade materials underlying the pavement result to the failure characteristics witnessed. This study shows that the suitability and behaviour of subgrade soil is dependent on its engineering properties.
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Jiang, Xunli, Zhiyi Huang und Xue Luo. „An Improved Mechanistic-Empirical Creep Model for Unsaturated Soft and Stabilized Soils“. Materials 14, Nr. 15 (26.07.2021): 4146. http://dx.doi.org/10.3390/ma14154146.
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Soft soils are usually treated to mitigate their engineering problems, such as excessive deformation, and stabilization is one of most popular treatments. Although there are many creep models to characterize the deformation behaviors of soil, there still exist demands for a balance between model accuracy and practical application. Therefore, this paper aims at developing a Mechanistic-Empirical creep model (MEC) for unsaturated soft and stabilized soils. The model considers the stress dependence and incorporates moisture sensitivity using matric suction and shear strength parameters. This formulation is intended to predict the soil creep deformation under arbitrary water content and arbitrary stress conditions. The results show that the MEC model is in good agreement with the experimental data with very high R-squared values. In addition, the model is compared with the other classical creep models for unsaturated soils. While the classical creep models require a different set of parameters when the water content is changed, the MEC model only needs one set of parameters for different stress levels and moisture conditions, which provides significant facilitation for implementation. Finally, a finite element simulation analysis of subgrade soil foundation is performed for different loading levels and moisture conditions. The MEC model is utilized to predict the creep behavior of subgrade soils. Under the same load and moisture level, the deformation of soft soil is largest, followed by lime soil and RHA–lime-stabilized soil, respectively.
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Liu, Shuang, Panpan Guo, Xian Li, Kai Wang und Rui Tang. „Settlement Behavior of Composite Foundation with Deep Mixed Piles Supporting Highway Subgrades in Water-Rich Flood Plains“. Water 15, Nr. 11 (28.05.2023): 2048. http://dx.doi.org/10.3390/w15112048.
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The settlement behavior of composite foundations plays an important role in the serviceability and stability of the subgrade or other infrastructures supporting the foundation. However, in water-rich flood plains, due to the complexity of the soft soil properties, the settlement behavior has not been well understood. The objective of this study is to investigate the effects of various key factors on the settlement behavior of composite foundations with deep mixed piles supporting highway subgrade in water-rich flood plains. The investigated subgrade is in operation, and the vehicle load is taken into account. The G347AH Project is considered in this study. Several typical models for predicting composite foundation settlements are discussed. By performing three-dimensional finite difference analysis, a comparison is made between the settlement behavior of the natural foundation and the composite foundation with deep mixed piles. Based on the single factor sensitivity analysis and the multi-factor orthogonal experimental design, the effects of pile length, pile diameter, pile spacing, pile elasticity modulus, cushion elasticity modulus, and cushion thickness on the composite foundation settlement are captured. It is found that among these factors, the degree of influence of pile length is superior. The composite foundation settlements predicted by the models agree well with the field-monitoring data, with the error being about 8.42% and 6.38%, respectively, at two monitoring sections. The research conducted in this paper can effectively reduce the probability of various settlement-related disasters occurring on highway subgrades in water-rich flood plains. Moreover, the research has important theoretical guidance for design optimization in terms of settlement control of highway subgrades in soft soil areas.
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Su, Xiao Cheng, und Hai Zhen Liu. „Using the Finite Element Method Analysis of Tianjin 112 State Line Road Soft Soil Subgrade“. Applied Mechanics and Materials 501-504 (Januar 2014): 372–75. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.372.
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By using the finite element method we had studied the Tianjin Expressway Subgrade Settlement.Through the comparison of the reinforcement and the unreinforced two case we studied the principles of strengthening soft soil subgrade and results show that the mixing pile to improve the bearing capacity of the embankment foundation, reduce the settlement of foundation has played a very good role.The finite element method can reflect the nonlinear characteristics of the coupling effect between composite foundation pile, soil and the soil around the pile, the soil using elastoplastic model, and considering the different medium, different distribution,which has great advantages in the analysis of various factors.The finite element method can better reflect the reinforcement of soft soil subgrade.So ,it also can optimize the engineering design.
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Yuan, Yu Qing, Wei Li, Xue Chan Li und Tao Guo. „Vibro-Replacement Stone Column Treating Silty Sand Soil Subgrade“. Applied Mechanics and Materials 256-259 (Dezember 2012): 1060–63. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1060.
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To improve the wet soft silty sand bearing capacity, vibro-replacement stone column was used. Compared with the practical construction, this paper introduces the vibro-replacement stone column strengthening soft foundation. The principle of the construction, quality control, and inspection technology were discussed. Based on Drucker - Prager elastic-plastic model, different high wet soft foundation was simulated with the numerical analysis software. Results show that vibro-replacement stone column can significantly reduce the roadbed horizontal displacement. The displacement of the subgrade reinforced by stone columns decreases respectively 0.1, 0.2, 0.6, 2.3 cm than the other. If the subgrade is 4 m in height, the displacement reaches 0.2, 0.5, 0.7 cm when the length of stone column is 5, 10, 15m, respectively. To sum up, five - metre long pile is more economic and reasonable.
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Hossain, Md Belal, Md Roknuzzaman, Md Asib Biswas und Motaharul Islam. „EVALUATION OF ENGINEERING PROPERTIES OF THERMAL POWER PLANT WASTE FOR SUBGRADE TREATMENT“. Journal of Civil Engineering, Science and Technology 12, Nr. 2 (30.09.2021): 112–23. http://dx.doi.org/10.33736/jcest.3975.2021.
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Soft cohesive soils have low strength, high plasticity, and a large expansion ratio making them unsuitable as a road subgrade. This study aims to evaluate the potential of power plant waste (fly ash) from the Barapukuria Thermal Power Plant, Dinajpur, Bangladesh to improve the characteristics of such soft cohesive soil. X-ray fluorescence test conducted to classify the power plant fly ash and the type was identified as “Class F” according to “American Association of State Highway and Transportation Officials” and "American Society for Testing and Materials". Laboratory tests were conducted on clay soil obtained from Dinajpur region modified by the collected power plant waste. As the Class F fly ash has low cementing property, 3% cement was added with it. Cement mixed soil was modified with 5%, 10%, 15%, and 20% fly ash respectively. Specific Gravity, Atterberg limits, Modified Proctor Compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests were conducted. The study reveals that there is a decrease in specific gravity, dry density, and plasticity index with the addition of power plant waste. On the other hand, there is an increase in optimum moisture content, UCS, and CBR value. UCS and CBR values were found to be improved remarkably. Soaked CBR value of soil is found to be improved from 2.79% to 92.59% when treated with 5% fly ash and 3% cement. The UCS value of this modified soil was 560.36 kPa. The stabilized soil thus obtained meets the requirements for subgrade as specified by the Local Government Engineering Department (LGED)’s design manual (2005), Bangladesh. Since there is a possibility of leaching by dumping a large quantity of fly ash in the pond, the use of fly ash from the power plants to improve soft cohesive soils for road subgrade may be an environment-friendly alternative to its disposal in the ponds.
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Wu, Da Zhi, und Zhen Ying Zhang. „Study on the Settlement of Soft Soil Subgrade with a Crust Layer“. Applied Mechanics and Materials 505-506 (Januar 2014): 82–88. http://dx.doi.org/10.4028/www.scientific.net/amm.505-506.82.
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By using the finite element method, the settlement of soft soil subgrade with a crust layer has been investigated. To find the influence of thickness of the crust layer on the settlement, four different thicknesses, which are 0.0m, 1.5m, 3.5m and 5.5m, are selected. Besides, the settlement during the construction and post construction are also analyzed. It is found that the crust layer can reduce the settlement and uneven settlement of subgrade effectively. Besides, the settlement of the subgrade decreases with the increase of the thickness of crust layer. Moreover, with the increase of time, the uneven settlement of the pavement increases gradually. And when the time is up to a certain degree, the uneven settlement tends to be stable.
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Zuo, Shen, Tian-yu Li, Peng Jiang, Xiang-long Zuo und Jin Li. „Study on the In Situ Test of the Treatment Effect for the Riverbank Soft Soil Subgrade in the Hetao Area“. Geofluids 2022 (30.07.2022): 1–12. http://dx.doi.org/10.1155/2022/9410466.
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The Inner Mongolia Hetao area has a widely distributed riverbank fluvial soft soil with high groundwater levels and ground surface water. This situation may incur some potential engineering problems for the Linhe-Baigeda section of the Beijing-Xinjiang Expressway, such as subgrade settlement control and waterproofing. In situ experiments were conducted on the site using five subgrade base treatment schemes for subgrade construction. The long-term monitoring of various technical indicators like settlement, earth pressure, pore water pressure, and reinforcement material deformation was carried out. Study results show that the cumulative settlement generated when the double-layer geogrid reinforces the subgrade base is 6.9 cm, which is the smallest among the five subgrade base reinforcement methods, and the cumulative settlement of the subgrade base reinforced with a single-layer geocell is the largest, which is 15.4 mm. The size and distribution of subgrade earth pressure change significantly during farmland irrigation. When the single-layer geocell reinforces the base, the subgrade stress is smaller than that of the other four, and the average earth pressure is 8 kPa. The membrane-pulling effect of reinforcement material significantly disperses the upper load of subgrade backfill soil, and the subgrade settlement control with different base treatment schemes meets the technical requirements.
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Wang, Xin, Xizhao Wang, Guangqing Yang, Changyu Pu und Jinzhao Jin. „Field Test on Deformation Characteristics of Pile-Supported Reinforced Embankment in Soft Soil Foundation“. Sustainability 14, Nr. 13 (27.06.2022): 7805. http://dx.doi.org/10.3390/su14137805.
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In this work, the settlement deformation of the soft-soil subgrade and the deformation law of the geogrid were studied based on field tests carried out on the pile-supported reinforced embankment of the Rongwu Expressway in the Xiong’an New Area. The settlement and deformation law of the reinforcement area and the underlying layer of the pile-supported reinforced embankment, the settlement law of the transverse and longitudinal sections of the subgrade, and the deformation law of the bidirectional geogrid were analyzed. The results show that reducing the pile spacing and embankment height can effectively reduce the foundation settlement. The change in the pile spacing mainly affected the settlement in the reinforcement area, while the embankment height mainly affected the substratum settlement; the differential settlement in the subgrade cross-section was mainly caused by the settlement in the reinforcement area. The settlement at the center of the subgrade was obviously higher than that at the shoulder. In terms of the geogrid deformation law of the subgrade cross-section, the geogrid deformation at the center line of the subgrade was the largest. With the increase in the distance from the center line, the geogrid deformation gradually decreased. In terms of the deformation law of the biaxial geogrid, the tensile deformation of the geogrid in the center of two piles was greater than that in the center of four piles. The transverse tensile deformation of the geogrid was greater than the longitudinal tensile deformation. The tensile stress of the reinforced materials was calculated according to four specifications, and the applicability of various methods was evaluated.
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Lawton, Evert C., Anagha A. Mokashi und Nathaniel S. Fox. „Field Tests and Numerical Analyses of Subgrade Soil Reinforced with Grids of Stabilized Granular Columns“. Transportation Research Record: Journal of the Transportation Research Board 1534, Nr. 1 (Januar 1996): 72–79. http://dx.doi.org/10.1177/0361198196153400111.
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Field tests and numerical analyses conducted to establish the feasibility of reinforcing soft, loose, or otherwise inadequate subgrade soils with a grid of small-diameter, stabilized, vertical granular columns to support traditional pavement systems are described. This technique may prove to be cost-effective if it is used to improve subgrade soils so that the sub-base or base courses can be reduced in thickness or eliminated. Field plate bearing tests were carried out on unreinforced cohesionless silty sand and on the same soil reinforced with vertical reinforcing columns constructed of four materials: crushed granitic gneiss, silica sand, cement-stabilized native soil, and cement-stabilized silica sand. The field tests indicated that the columns made of the two cement-stabilized materials substantially increased the subgrade modulus of the native soil. In contrast, the two unstabilized columnar reinforcing materials produced no substantial improvement in stiffness. The field tests were modeled by using an axisymmetric finite-element (FE) program and hyperbolic constitutive relationships for the native soil and the columnar reinforcing materials. Triaxial tests were performed on reconstituted specimens of the native soil and compacted specimens of cement-stabilized native soil to determine the stress–strain–strength parameters required for the FE analyses. The FE analyses modeled the plate bearing tests on the reinforced soil to a reasonable degree, indicating that the FE method used has the potential to simulate a complete pavement system (including a wearing surface) in which the subgrade soil is reinforced with columns of stabilized granular materials.
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Marques, Alexandre, S. Syahril und Elfrido Elias Tita. „The effect of lime and phosphoric acid on the CBR value of soft soil based on curing time“. E3S Web of Conferences 479 (2024): 06001. http://dx.doi.org/10.1051/e3sconf/202447906001.
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Road construction, both for flexible and rigid pavements, needs to pay attention to the bearing capacity of the subgrade. Especially on soft clay soils. The method to determine the bearing capacity value is through CBR testing in the laboratory. Soft soil has a low bearing capacity, so it cannot accept the load acting on it, such as the soil in the Gedebage area of Bandung. Because the carrying capacity value is decreasing, it is necessary to improve the soil with soil stabilization methods. In this research, stabilization materials will be used in the form of lime with a percentage of 10% and phosphoric acid 5%. Aiming to increase the bearing capacity value of the soil based on the results of laboratory CBR tests with 3, 7, and 14 days of curing, as well as to determine the optimum curing period of the test. Based on the test results, very positive results were obtained because it can increase the soaked CBR of 0.8% and 3% unsoaked for the native soil to 5.6% for soaked and 15.23% for unsoaked CBR in soil that has been stabilized with a 14-day curing period. Thus, these stabilization results meet the minimum requirements for pavement subgrade.
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Guo, Yuan Cheng, und Hai Tao Liu. „Deformation Analysis and Engineering Practice of Post-Processing Method in Thick Filled Subgrade“. Applied Mechanics and Materials 97-98 (September 2011): 247–50. http://dx.doi.org/10.4028/www.scientific.net/amm.97-98.247.
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Expressway is developed quickly in China, but its construction is seriously affected by the un-uniform deformation of the subgrade. The basic concepts of post- treatment and pre- treatment on freeway subgrade are firstly discussed in this article, and then a conclusion that Post- treatment Method can obviously reduce the after-work sink is gained, which may be used as a practical reference for lighting the un-uniform deformation of thick-filled subgrade in soft-soil area.
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Sianturi, Novdin Manoktong, Mohd Khairul Amri Kamarudin, Dermina Roni Santika Damanik, Virgo Erlando Purba und Deardo Samuel Saragih. „The Mechanical Behavior of Soft Soil Stabilized with Lime and Volcanic Ash“. MEDIA KOMUNIKASI TEKNIK SIPIL 28, Nr. 1 (29.07.2022): 118–27. http://dx.doi.org/10.14710/mkts.v28i1.41963.
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The properties of soft clay can be seen from the compressive strength value through the unconfined compressive strength (UCS) test. Soft soil was less well used as the subgrade for construction. The aim is to determine the increase in the unconfined compressive strength and bearing capacity of the foundation due to the addition of lime and volcanic ash on soft soil. Soft soil has undrained shear strength < 25 kPa based on the unconfined compressive strength test. The unconfined compressive strength test has been conducted on the soil-lime mixture and soil-volcanic ash mixture of 3-12% respectively to the weight of dry soil. The highest unconfined compressive strength values were found in soils with 6% of lime and 9% of volcanic ash. The bearing capacity of the foundation on soil stabilized with 6% lime increased 13.7 times, while the bearing capacity of the foundation on the soil with the addition of 9% volcanic ash increased the ultimate bearing capacity of 8.7 times the bearing capacity of the foundation on soft soil. The bearing capacity of the foundation on lime stabilized soil is higher than the bearing capacity of the foundation on volcanic ash stabilized soil.
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Šiukščius, Aurimas, Viktoras Vorobjovas, Audrius Vaitkus, Šarūnas Mikaliūnas und Atis Zariņš. „Long Term Behaviour of An Asphalt Pavement Structure Constructed on a Geogrid-Reinforced Subgrade Over Soft Soils“. Baltic Journal of Road and Bridge Engineering 14, Nr. 3 (26.09.2019): 384–404. http://dx.doi.org/10.7250/bjrbe.2019-14.449.
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Many roads with asphalt pavement are being reconstructed every year, as their quality becomes insufficient by the requirements. As it is well- known, old roads were built not in the very best quality, so doing reconstruction projects in the most cases there were required to deal with soft soils that are under the existing road structure. Geogrid reinforcement was widely used to solve issues of soft soil in Lithuania. There are projects where geogrid reinforcement is used to control road pavement roughness when there are layers of peat or silt under road structure instead of using concrete piles or geosynthetic-encased soil columns. This type of geogrid reinforcement application is unexplained in any normative-technical document but widely used in Lithuania. This application was usually made constructively without any calculations, choosing the reinforced solution by reducing the geogrid tensile strength or layer quantity compared to reinforced load transfer platform over piles. This paper evaluates the long-term influence of geogrid- reinforced subgrade on the roughness of asphalt surfacing and bearing capacity of the road structure when the soft peaty soils stratify in the deeper layers of the subgrade. There were compared the reinforced sections to adjacent sections to see the effect and fortunately a large number of adjacent sections were also strengthened, mostly by lime stabilisation. Therefore, this comparison allows making more insights on the long-term performance of the strengthened subgrade and influence on the road quality. This research gives recommendations on how the geogrids has to be selected to be used in this kind of application.
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Sahoo, Ayusman Mahaprasad, Subash Chandra Murmu, Dipti Ranjan Patra und Sanam Sarita Tripathy. „Static Behaviour of Geo-Cell Confined with Reinforced Soft Clay Soil“. International Journal for Research in Applied Science and Engineering Technology 11, Nr. 6 (30.06.2023): 2712–15. http://dx.doi.org/10.22214/ijraset.2023.54101.
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Engineers often experience difficulties in starting any construction work on soft clay because there is no hard strata at a depth of 15 m. The application of a Geo-cell structure provides a comparatively harder stratum at the top of the soft subgrade. Therefore, experimental investigations have been carried out on the stability of a Geo-cell reinforced soft soil structure, to evaluate the effect of the Geo-cell.
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Arifin, Y. F., und R. F. Rahmah. „Stabilization of Soft Clay from Bukit Rawi using Portland Composite Cement“. IOP Conference Series: Earth and Environmental Science 999, Nr. 1 (01.03.2022): 012027. http://dx.doi.org/10.1088/1755-1315/999/1/012027.
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Abstract One method for stabilizing soft clay is to mix it with cement. Portland composite cement (PCC) is a cement produced by grinding together portland slag and gypsum with one or more inorganic materials that is suitable for stabilization of soft soils. The purpose of this study was to mix soft clay from Bukit Rawi, Central Kalimantan with PCC, which was then tested for unconfined compression strength (UCS) and the California Bearing Ratio (CBR) to see if it could be used as a road subgrade. Soft soil from Bukit Rawi was mixed with PCC with percentages of 6%, 8%, 10%, and 12% on a dry weight basis. The mixture was tested by Proctor standard compaction to obtain the optimum moisture content and maximum dry density. At these optimum conditions, UCS and CBR tests were carried out. The findings reveal that adding PCC to Bukit Rawi soil enhances UCS and CBR, which were previously 3.47% of CBR and 0.67kg/cm2 of UCS. The addition of PCC with a level of 2‒3% is planned for field application, because it is considered capable of fulfilling the requirements as a subgrade layer with a CBR of 15%. Furthermore, 12 percent PCC is required in the combination as a foundation (minimum 20kg/cm2 of UCS).
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Prakash Shrirao, Shubham, und Sukhanand Sopan Bhosale. „Geocell Reinforced Soil/Subgrade: Comparative Study of Bearing Capacity Evaluation Methods“. Journal of University of Shanghai for Science and Technology 23, Nr. 06 (17.06.2021): 595–605. http://dx.doi.org/10.51201/jusst/21/05301.
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At present, rapid urbanization results in enormous infrastructure growth, which led engineers to face construction challenges over soft soil or weak sub grade. Many soil stabilization approaches have been established as a viable way to overcome this hindrance. Among all the ground improvement techniques, geocell, being a three-dimensional form of geosynthetics, is often used to enhance the bearing capacity of soft soils. This paper discusses analytical methods developed by researchers Presto (2008) [1], Koerner (2012) [2], Avesani Neto et al. (2013) [3], and Sitharam and Hedge (2013) [4] to evaluate the bearing capacity of soil reinforced with geocell. The paper also compares the results of these methods with those of laboratory experiments conducted by Dash et al. (2003b) [5] and Emersleben and Meyer (2008) [6]. Researcher Dash et al. used cohesive soil in foundation, while Emersleben and Meyer used c-ɸ soil in foundation. The comparisons show that researchers Koerner and Presto underestimate the bearing capacity when compared with experimental results of both Dash et al. and Emersleben and Meyer. Whereas authors Avesani Neto et al. and Sitharam and Hegde offer the best fit with experimental results of Dash et al. But, with Emersleben and Meyer’s experimental results, Avesani Neto et al. gives the overestimated results, while Sitharam and Hegde partially agree for lower geocell aspect ratios beyond settlement equal to 35% of footing diameter.
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Ibrahim, Anas, Azura Ahmad, Muhammad Luqman Azuddin Fitri, Noryani Natasha Yahaya, Faizah Kamarudin und Muhammad Sofian Abdullah. „Resistivity Determination of Railway Track’s Subgrade“. ESTEEM Academic Journal 19, March (01.03.2023): 91–100. http://dx.doi.org/10.24191/esteem.v19imarch.21166.
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The conventional geotechnical investigation method using borehole drilling and sampling was usually performed for subsurface exploration. However, it is -time-consuming, invasive and requires the closing of railway lanes that disrupts the train service. To avoid this problem, a geophysical method is an alternative that can be proposed to assess the conditions of the soil subgrade under the railway track. Electrical resistivity is one of the geophysical methods that study the nature of the electricity flow in the soil by injecting the electric current into the soil and measuring the generated potential difference. The field investigation was conducted at two different locations using electrical resistivity methods to identify the properties of the soil. Two railway track site locations selected were Pinang Tunggal, Pulau Pinang (KM 23), and Alor Setar, Kedah (250 m from the station in the north direction). ABEM Terrameter LS was used in field work that applied two configurations of an array, the Wenner and Schlumberger arrays, to infer the subsurface soil layer. The results concluded that the apparent resistivity data need to be inverted into an actual resistivity data set using Resistivity 2D Inversion (RES2DINV) software. The analysis found that the soil properties are both classified as soft soil with electrical resistivity values ranging from 0 - 100 Ω-m.