Behavior of Square Footing Resting on Gypseous Soil and Surrounded by a Sheet Pile Wall

Laboratory model is used in this study to investigate the behavior of centrally loaded square footing resting on gypseous soil, and surrounded by a sheet pile wall at a distance of 2B from the footing edge and extend in depth to 2B as well. During this study the soil were subjected to ten cycles of saturation and drainage at one-week interval to simulate heavy rainfalls or floods. It should be noted that the soaking water were added only outside the area surrounded by the sheet pile. Four points were chosen to detect gypsum solubility, three of them below the footing edge at different depths and one outside the sheet pile wall for comparison. It has been found that the dissolved gypsum below the footing is significantly less than the one outside the sheet pile wall. For each cycle of saturation-drainage the gypsum content is found to be reduced by 3 % and 0.8 % for the outsider point and for average of the three points respectively. Settlement during first cycle of saturation – drainage was twice as the second cycle and about four times of the third cycle. However, this first cycle settlement is about 25 % of the settlement of footing where no sheet pile wall is used. To sum up, the sheet pile wall found to be an effective protection to reduce the collapsibility of gypsum soil and to reduce footing settlement.

Study on slope stability of frame prestressed anchor sheet pile wall with finite element strength reduction method

Slope stability analysis is performed in practical geotechnical engineering using the finite element method, which is an advanced method and is widely used by engineers. With the development of computer technology, it has become easy to study the slope's stability supported by frame prestressed anchor and sheet pile wall through the displacement-based finite element numerical analysis method, to calculate the safety factors. However, the expansion angle ψʹ is not widely covered. In this study, PLAXIS two-dimensional finite element method is using to establish the slope model supported by frame prestressed anchor and sheet pile wall, and the influence of expansion angle on slope deformation is studied. The results show that the expansion angle has a different effect on the convergence of the two-dimensional slope model. In the model slope, a prestressed frame anchor and sheet pile wall reinforce the slope. The failure mechanisms were unclear when ϕʹ= ψʹ (flow base). Besides, when the slope has high soil strength parameters (c' or φʹ), the expansion angle will affect the calculation results and convergence. In general, the expansion angle significantly influences the slope's stability and is not affected. Therefore, it was necessary to note the effect of the angle of expansion on stability.

Investigation of Influencing Factors on the Deformation of Sheet Pile Wall with a Relieving Platform

Owing to the complexity of the sheet pile wall with a relieving platform, there are a large number of factors that affect the mechanical and deformation characteristics of the wall structure. Moreover, studying the influencing factors on the deformation of the retaining wall is beneficial in the selection of design parameters and deformation control. 28 groups of test models of the retaining wall structure are designed to analyze the effect on the deformation of rib pillars and determine the reasonable width and buried depth of the unloading board in this paper. The tests are conducted with and without the unloading board, and different widths and buried depths of the unloading board are also considered. The findings show that, without the external load, the reasonable board width and buried depth are 0.70 times and 0.53 times the wall height. With the external load, the reasonable board width is 0.35 times the wall height, and the large board width cannot effectively reduce the deformation of rib pillars, and the reasonable board width is 0.60 times the wall height. When both the external load and board width are relatively small, the reasonable buried depth is 0.53 times the wall height. However, when the external load is large, the reasonable buried depth is 0.70 times the wall height. The results also show that the setting of the unloading board effectively suppresses the deformation of rib pillars and controls the maximum deformation within an allowable range of the specification.

Parametric Study of Sheet Pile Wall using ABAQUS

In the present study two-dimensional finite element analysis has been carried out on cantilever sheet pile wall using ABAQUS/Standard software to study the effect of different friction angles and its related parameters such as dilation angle, the interfacial friction coefficient between soil-wall on earth pressure distribution, and wall deformation. From the results obtained, it is found that there is a significant decrease in wall deformation with an increase in the angle of internal friction and its related parameters. The earth pressure results obtained from the finite element analysis shared a unique relationship with that of a conventional method. Both the results showed similar linear behavior up to a certain percentage of wall height and then changed drastically in lower portions of the wall. This trend of behavior is seen in both active as well as in passive earth pressure distribution for all the frictional angle. Hence, after comparing the differences that exist in the results for both methods, from the analysis a new relationship between the earth pressure coefficients from a conventional method and the finite element method has been developed for both active and passive earth pressure on either side of the sheet pile wall. This relationship so derived can be used to compute more reasonable earth pressure distributions for a sheet pile wall without carrying out a numerical analysis with a minimal time of computation. And also the earth pressure coefficient calculated from this governing equation can serve as a quick reference for any decision regarding the design of the sheet pile wall. Doi: 10.28991/cej-2021-03091638 Full Text: PDF