Study On The Influence Of Cable Structure Parameters On The Potential Slip Surface Of Foundation Pit Under The Condition Of Pile Anchor Support

The soil on the lateral wall of the foundation pit is always sliding along the potential slip surface. The shape, location of the potential slip surface and the relative safety factor are determined by the composition, formation structure, boundary and the surrounding environmental conditions in foundation pit. The redistribution of stress and strain during the excavation may cause large deformation or the failure of the whole side wall. Pile-anchor supporting as one of the most common support forms in deep foundation, the anchor cable plays a very important role in controlling the deformation and helping reach the goal of ensuring the safety and stability so that increase the safety factor in foundation pit. Different cable length, angle and arrangement form will influence the reinforcement effect which reflected on the change of potential slip surface. To make the reinforce design more effective, pertinence and economic, it is necessary to study the influence of anchor cable structure parameters on the potential slip surface of foundation pit in Pile-anchor system.In this paper, finite difference software FLAC 3D was referenced to establish some two-dimensional models of anchor Support System. By changing the length of free segment, arrangement form and inclination to study the variation of potential slip surface and safety factor in Pile-anchor System. Then check the results of numerical simulation by Lizheng Deep Foundation, the comparison validated the correctness of the conclusion. So as to reveal the influence of anchor parameters on the potential slip surface and propose the application scope of the discipline. Finally, applied the numerical simulation results to demonstrate the support scheme of the 14.6m deep foundation named Rui Dingcheng in Kunming. The results show that the scheme is the most economic support program in the context of ensuring the overall stability, overturning stability and resistance heave stability.The research conclusions are as follows:1. The potential slip surface moves to the outside of the foundation pit along with the anchor root location with the increasing of the free length when fixed the other factors in Pine-anchor System, then with the free length go on rising the potential slip surface mutates to the inside of the pit finally stay on somewhere with the free length continue increasing. The safety factor increases when the potential slip surface moves to the outside of the foundation pit with the raising of the free length, until the potential slip surface remaining constant, the safety factor stays the same.2. When holding on the total length of free segment of cable in pile anchor support system, the potential slip surface tending to the outside when the anchor upper row is shorter, and with the increasing of total length of free segment, the potential slip surface is the first one mutating to the inside of the pit in this arrangement form. The safety factor when the upper row is shorter is bigger than the under row is shorter and the equal length of three row.3. The potential slip surface moves along with anchor root to the outside of the foundation pit with the increasing inclination of anchor in pile anchor support system, then continue to increase the angle of anchor inclination the potential slip surface moves inside of the pit in a heartbeat finally nearly stay on somewhere with the increase the angle of anchor inclination continue increasing. The safety factor is the biggest when the potential slip surface suddenly moves to the inside.4. When the potential slip surface moves to the outside of the pit with the anchor parameters change in pile-anchor structure, the safety factor will get bigger. After mutation to the inside pit the safety factor reaches a maximum. The length of free segment, the arrangement and the inclination at this time is the form which can increase the safety factor to the maximum.5. Theory must be closely integrated with practice. The support design of deep foundation should be adjusted according to the actual construction conditions, difficulty, cost and other factors.