Numerical Simulation Of Pile Anchor And Soil Nailing Wallcombined Timbering In Deep Foundation Pit

Based on the background of a deep foundation pit supporting project in Shijiazhuang, the combined support structure of row of piles pre-stress anchor bolt supporting and soil nailing wall is designed according to the requirement of the surrounding environment. Through analyzed the measuring data and numerical simulation of segmental combination of pile anchorage supporting structure and soil nail wall supporting structure, the results showed that the pile anchorage supporting structure had a certain effect on the deformation of the soil nailing wall supporting structure and the conclusions reached are as follow:(1)Based on the analysis of experiment data, the horizontal displacement deformation rate of segmental combination of pile anchorage supporting structure decreased from 30% to40% combined with soil nail wall supporting structure, and the vertical displacement decreased from 10% to 30%. The lateral earth pressure of two kinds of supporting structure increased with the increasing depth. Compared with the calculated values, it was also basically consistent.( 2) Through the analysis of horizontal and vertical displacement in two kinds of supporting structure: both maximum displacement was at the central region of the foundation pit. The minimum displacement occurred at the corner. From the middle to the 1/4 position of the foundation pit, the horizontal displacement of the soil nailing wall decreased by 1%,the vertical displacement decreased by 1%;And the horizontal displacement of the combined support structure decreased by 22%, the vertical displacement decreased by 51%. The horizontal displacement of the pile foundation of the combined supporting structure decreased by 20%-30% compared with the soil nailing wall. The vertical displacement decreased by60%-70%; when reached the middle of the foundation pit and backward extension, the change rate of horizontal displacement decreased by 1%-2%, the change rate of vertical displacement decreased by 15%-20%.( 3) Through the analysis of deep soil horizontal displacement in two kinds of supporting structure: the maximum deep soil horizontal displacement of pile anchorage supporting structure was at 0.5-0.6 times the depth of the foundation pit;the maximum deep soil horizontal displacement of soil nail wall supporting structure was at 0.5 times the depth ofthe foundation pit and the top of foundation pit; with the increase of the depth of foundation pit, the advantage of the pile anchorage supporting structure is more obvious.( 4) The maximum vertical displacement of the pipeline in the form of combined support and soil nailing wall was found at 0.25 times the length of the foundation pit, it was the farthest distance from the pit angle. The minimum vertical displacement was found in the length of the foundation pit 0.1 times outside the foundation pit. The combined supporting form was decreased by about 60% of the pipeline deformation compared with the soil nailing wall.