The Stability of Unsaturated Soil Foundation Pit Reinforced with the Cement-Mixed Sheet Pile Wall

2011 ◽  
Vol 142 ◽  
pp. 243-246
Author(s):  
Rong Jian Li ◽  
Hao Duan ◽  
Wen Zheng ◽  
Hai Tao Li
Keyword(s):  
Safety Factor ◽  
Unsaturated Soil ◽  
Matric Suction ◽  
Sheet Pile ◽  
Foundation Pit ◽  
Constant Height ◽  
Overall Stability ◽  
Soil Foundation ◽  
The Stability ◽  
Sheet Pile Wall

The non-uniform distribution of matric suction in the unsaturated soil has a great impact on the stability of the unsaturated soil foundation pit. By means of the strength reduction finite element method, the stability of the unsaturated soil foundation pit reinforced with the cement-mixed sheet pile wall was analyzed. The overall safety factor of the unsaturated soil foundation pit reinforced with the cement-mixed sheet pile wall is greatly reduced and the position of potential sliding surface goes upward with the gradually decreasing of matric suction. With the constant height of the cement-mixed sheet pile wall, the shallower the embedding depth of the cement-mixed sheet pile wall is, the smaller the safety factor of the foundation pit slope is. The results show that the safety factor of the overall stability of the unsaturated soil foundation pit decreases with the deep excavation and the gradually decreasing of the matric suction.

scholarly journals Safety Factor of Unsaturated Soil Slopes considering the Intermediate Principal Stress Effect and Different Profiles of Matric Suction

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhaoxin Li ◽  
Changguang Zhang ◽  
Jingyuan Zhao ◽  
Qing Yan
Keyword(s):  
Shear Strength ◽  
Principal Stress ◽  
Safety Factor ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Matric Suction ◽  
Intermediate Principal Stress ◽  
Stress Effect ◽  
Soil Slopes ◽  
The Stability

Profiles of matric suction are critical for assessing the stability of unsaturated soil slopes, and the strength of unsaturated soils is affected by the intermediate principal stress. This study presents a theoretical formulation of safety factor for infinite unsaturated soil slopes under four different profiles of matric suction using the limit equilibrium method. The unified shear strength equation under plane strain conditions is adopted to capture the effect of intermediate principal stress on the strength of unsaturated soils. The proposed formulation of safety factor is found to have good comparability and broad applicability. The validity of the proposed formulation is demonstrated by comparing its predictions with the results of the extended shear strength method and the finite element method available in the literature. Parametric studies show that the effect of intermediate principal stress on the stability of unsaturated soil slopes is significant; the difference of safety factor among four suction profiles is pronounced, and the safety factor is highest for a linear suction profile. In addition, the safety factor changes with the infiltration depth in two stages, decreases with the slope angle, and increases with effective strength parameters. The results of this study are capable of providing beneficial guidance for optimization designs and disaster preventions of unsaturated soil slopes.

scholarly journals DESIGN OF RETAINING WALL USING ALTERNATIVE GABION AND RETAINING WALLS OF CANTILEVER TYPE ON SLOPE OPEN SPACE GREEN JL. KINIBALU BANJARBARU

CERUCUK ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 69
Author(s):  
Adelina Melati Sukma
Keyword(s):  
Stability Analysis ◽  
Safety Factor ◽  
Carrying Capacity ◽  
Rainy Season ◽  
Open Space ◽  
Retaining Wall ◽  
Retaining Walls ◽  
Stability Calculation ◽  
Overall Stability ◽  
The Stability

On the construction of green open space Jl. Kinibalu Banjarbaru There is a 6 meters tall slope beneath which the river is lined up during the rainy season and makes the slope exposed by water plus the absence of load or traffic on it make the pore figures on the land is large. Therefore, for protection reason, there is a soil alignment in the construction of soil retaining walls. The planned ground retaining wall type is cantilever and gabion. The stability analysis of the ground retaining walls is done manually and with the help of the Geoslope/W 2018 software. The value of the stability of the style against the bolsters, sliding, and carrying capacity of the soil using manual calculations for cantilever type and Netlon qualifies SNI 8460:2017. And for the overall stability calculation using Geoslope/W 2018 software obtained safety factor (SF) > 1.5. From the analysis, the design of planning can be used because it is safe against the dangers of avalanche.

scholarly journals Stability analysis of rock slope and calculation of rock lateral pressure in foundation pit with structural plane and cave development

2021 ◽  
Author(s):  
Jin Xu ◽  
Yansen Wang
Keyword(s):  
Safety Factor ◽  
Rock Slope ◽  
Lateral Pressure ◽  
Rock Foundation ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Failure Characteristics ◽  
Karst Caves ◽  
Geological Conditions ◽  
The Stability

Abstract In this study, numerical simulations were carried out to analyze the influence of caves in different positions and shapes, in combination with structural planes, on the stability of the slope and the failure characteristics of a rock slope in a deep foundation pit with high inclination structural planes and cave development. The schemes for substituting a single karst cave for karst caves were constructed. Based on the penetration failure characteristics of karst caves between parallel structural planes, methods for calculating the safety factor of the rock foundation pit and the upper bound of the lateral pressure of the supporting structure under the combined influence of the caves and structural planes were developed, which can be used to assess the safety factor of a rock mass and to calculate the lateral pressure under complex geological conditions.

Stability Analysis of Unsaturated Soil Slopes Based on Unified Strength Theory

2013 ◽  
Vol 353-356 ◽  
pp. 946-951
Author(s):  
Yan Li ◽  
Jun Hai Zhao ◽  
Qian Zhu ◽  
Chang Guang Zhang ◽  
Wen Qi Bai ◽  
...  
Keyword(s):  
Principal Stress ◽  
Unsaturated Soil ◽  
Research Result ◽  
Friction Angle ◽  
Matric Suction ◽  
Intermediate Principal Stress ◽  
Unified Strength Theory ◽  
Stability Coefficient ◽  
Soil Slopes ◽  
The Stability

Based on the unified solution of shear strength in terms of double stress state variables for unsaturated soils, the unified formula of stability coefficient for unsaturated soil slopes under the plane strain condition is derived by Sweden slice method, which considers the effect of the intermediate principal stress rationally. Combining with engineering example, the proposed formula is compared with the one that is on the basis of Fredlund unsaturated soil theory and the influencing characteristics of factors including intermediate principal stress, matric suction, effective internal friction angle and matric suction angle is obtained. The research result indicates that: intermediate principal stress and matric suction have obvious impacts on the stability coefficient for unsaturated soil slopes; the stability coefficient has been increasing with the increase of unified strength theory parameter and matric suction, which proves that the consideration of intermediate principal stress and matric suction can make slopes give full play to their self-stabilities and strength potential, and the yield criterion has great impact on the judgment of slope stability; the stability coefficient also increases nonlinearly with the increase of effective internal friction angle and matric suction angle. The proposed unified formula of stability coefficient for unsaturated soil slopes enjoys a wider application. The stability coefficient for unsaturated soil slopes according to the Fredlund unsaturated soil theory and that for saturated soil slopes are just the special cases. The research result can provide theoretical basis for stability analysis and reinforce design of the unsaturated soil slopes, and it is of great significance to the slope management.

Target reliability based design optimization of anchored cantilever sheet pile walls

2008 ◽  
Vol 45 (4) ◽  
pp. 535-548 ◽  
Author(s):  
B. Munwar Basha ◽  
G. L. Sivakumar Babu
Keyword(s):  
Failure Mode ◽  
Steel Sheet ◽  
Target Component ◽  
Sheet Pile ◽  
Limit States ◽  
Reliability Based Design ◽  
Section Modulus ◽  
Reliability Method ◽  
The Stability ◽  
Sheet Pile Wall

In this study, the stability of anchored cantilever sheet pile wall in sandy soils is investigated using reliability analysis. Targeted stability is formulated as an optimization problem in the framework of an inverse first order reliability method. A sensitivity analysis is conducted to investigate the effect of parameters influencing the stability of sheet pile wall. Backfill soil properties, soil – steel pile interface friction angle, depth of the water table from the top of the sheet pile wall, total depth of embedment below the dredge line, yield strength of steel, section modulus of steel sheet pile, and anchor pull are all treated as random variables. The sheet pile wall system is modeled as a series of failure mode combination. Penetration depth, anchor pull, and section modulus are calculated for various target component and system reliability indices based on three limit states. These are: rotational failure about the position of the anchor rod, expressed in terms of moment ratio; sliding failure mode, expressed in terms of force ratio; and flexural failure of the steel sheet pile wall, expressed in terms of the section modulus ratio. An attempt is made to propose reliability based design charts considering the failure criteria as well as the variability in the parameters. The results of the study are compared with studies in the literature.

Analysis of the Influences of Matric Suction of Unsaturated Soil on the Slope Stability

2012 ◽  
Vol 170-173 ◽  
pp. 3186-3189 ◽  
Author(s):  
Li Wang ◽  
Cui Ran Liu
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Yellow River ◽  
Matric Suction ◽  
Saturated Soil ◽  
Equilibrium Method ◽  
Stability Of Slope ◽  
Ultimate Equilibrium ◽  
The Stability ◽  
Test Result

There is suction in unsaturated soil. This is the most obvious difference between unsaturated soil and saturated soil. It is very difficult to measure it, so research has always been done without account of the influences of matric suction of unsaturated soil. In this paper, based on the test result of engineering characteristics of unsaturated soil from Yellow River Embankments, the stability of slope of Yellow River Embankments is analyzed using ultimate equilibrium method and the influencing rule of matric suction on slope is advanced.

scholarly journals Numerical Investigation of a Foundation Pit Supported by a Composite Soil Nailing Structure

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 252 ◽  
Author(s):  
Wei Han ◽  
Genxiao Li ◽  
Zhaohui Sun ◽  
Hengjie Luan ◽  
Chuanzheng Liu ◽  
...  
Keyword(s):  
Side Wall ◽  
Horizontal Displacement ◽  
Middle Part ◽  
Soil Nailing ◽  
Foundation Pit ◽  
Soil Nails ◽  
Factors Affecting ◽  
Composite Soil Nailing ◽  
Soil Foundation ◽  
The Stability

In special geology conditions such as silt-soil, foundation pits are prone to instability and severe deformation. In this paper, a composite soil nailing structure was studied and its effect on a silt-soil symmetrical foundation pit investigated. The factors affecting the stability of the pit as well as its deformation characteristics were also explored. The results show that excavation depth of the foundation pit has a significant impact on its stability. The soil outside the foundation pit is in the form of a parabola, and the uplift of the soil mainly occurs at the bottom. The horizontal displacement of soil on the side wall of the foundation pit presents a “bulk belly” form. In addition, the axial force of soil nails is larger in the middle part, and smaller at both ends in the shape of a spindle. Moreover, the horizontal displacement is positively correlated with the inclination and spacing of the soil nails, but negatively correlated with the diameter and depth of the mixing pile inlay. Furthermore, the inclination and spacing of the soil nails, the diameter, and embedded depth of the mixing pile have their own critical values for stability of the foundation pit. Specifically, in this paper, with respect to soil nails, inclination should be below 30° and prestress value should not exceed 20 kN. With respect to the mixing pile, the diameter should be less than 1.5 m; when the embedded depth of the mixing pile exceeds the critical depth, the limiting effect of the mixing pile on horizontal displacement is not significant. This research provides important takeaways for the design of a composite soil nailing structure for symmetrical foundation pits.

The Stability Analyses of Unsaturated Slope Based on the Sarma Method

2011 ◽  
Vol 393-395 ◽  
pp. 1569-1573
Author(s):  
Rong Jian Li ◽  
Qiang Xu ◽  
Wen Zheng ◽  
Hung Chou Lin
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Geotechnical Engineering ◽  
Matric Suction ◽  
Computational Error ◽  
Computational Results ◽  
Soil Slope ◽  
Strength Theory ◽  
Stability Analyses ◽  
The Stability

The study of unsaturated slope stability is one of issues in geotechnical engineering. Firstly, the different treatments of matric suction in the Sarma method are analyzed based on the Bishop’s unsaturated strength theory and Fredlund’s unsaturated strength theory respectively. Then, application of the developed method on the stability analyses of an unsaturated soil slope is also discussed. Through the comparison on the computational results, it still can be concluded that the computational error is slights, which analyzed by means of the developed Sarma method based on the Bishop’s unsaturated strength theory and Fredlund’s unsaturated strength theory.

scholarly journals Sensitivity Analysis on Stability Parameters in Landfill

2015 ◽  
Vol 9 (1) ◽  
pp. 108-111 ◽  
Author(s):  
Sun Hong-Jun ◽  
Fan Yan-Chao ◽  
Zhao Li-Hong
Keyword(s):  
Safety Factor ◽  
Limit Equilibrium ◽  
Slope Angle ◽  
Friction Angle ◽  
Equilibrium Analysis ◽  
Stability Parameters ◽  
Limit Equilibrium Analysis ◽  
Sensitivity Curves ◽  
Overall Stability ◽  
The Stability

To study the stability of waste body failure in landfill, the landfill was divided into two parts: an active wedge and a passive wedge. A limit equilibrium analysis was used to calculate the safety factor of stability in landfill. The parameters which affected the stability of the landfill were discussed. Sensitivity curves of each parameter were proposed and effect trends of various parameters on safety factor were analyzed. Cohesion c and internal friction angle фs increases linearly with the safety factor. The safety factor decreases with increasing slope angle β and filled height H. The safety factor of after landfill settlement was higher than the safety factor of settlement which did not occur. It increases the overall stability about 16%.

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