| Summary: | 碩士 === 國立臺灣科技大學 === 營建工程系 === 103 === Slope stability is an important topic of geotechnical engineering and using drilled shafts is one of the feasible methods to stabilize the slope. According to previous studies, when a row of drilled shafts are installed in the slope, soil arching will be developed between the drilled shafts, resulting in the reduction of the sliding force. This effect can be evaluated by the load transfer factor; therefore, soil arching and load transfer factor warrant further research. Based on previous results, this study use PLAXIS 3D to investigate the groundwater effect of the slope stabilized using drilled shafts. Analysis and discussion items include horizontal stress, horizontal displacements, safety factor and load transfer factor.
Overall examination of horizontal stress, horizontal displacement, factor of safety and load transfer factor of this study show that PLAXIS 3D can give reasonable analytical results. Rising groundwater will affect both the slope stability and the load transfer behavior. When there is no groundwater and the water table is low (10m) such that it does not reach the sliding surface, the factor of safety is the same as 1.44. When the water table is high (21m) and near the top of the slope safety factor significantly reduces to 1.16. When the groundwater is raised larger displacements are observed no matter whether there is significant change in safety factor or not. For cases with groundwater, the load transfer factors also decrease with increasing safety factor. Study of the zig-zag pile arrangement with and without groundwater show that safety factor may increase slightly if the middle pile is moved upslope of a limited distance (2D). However, if the middle pile is moved downward safety factor may decrease significantly.
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