Mechanical characteristics and optimization design of pile-brace-soil combined supporting structure for deep foundation pit
Based on a deep foundation pit of a high-rise building,the deformation of the key parts of combined supporting structure and foundation pit subjected to different construction stages was obtained by field investigation.A three-dimensional numerical model of the combined supporting structure for deep foundation pits was established by using soil hardening model.The entire process of excavation construction was simulated,and the distribution rules of pile bending moment,pile displacement and soil pressure of supporting structure system were analyzed.Orthogonal tests were designed to analyze the sensitivity of the parameters that affected the deformation of the retaining pile,such as the width,the height and the slope of counterweight soil,the spacing and diameter of inclined braces.The optimization suggestion was proposed.The results show that the maximum displacement and the maximum positive bending moment of the retaining pile decrease with the increase of the top width and height of counterweight soil,and the diameter of inclined brace,and they increase with the increase of the slope of counterweight soil and the spacing of inclined braces.The sensitivity ranking of factors affecting pile deformation from large to small are height of counterweight soil,top width of counterweight soil,slope of counterweight soil,spacing of inclined brace and diameter of inclined brace.For the engineering design of the combined support system,it is recommended to increase the height of counterweight soil as much as possible when the stability angel of counterweight soil slope is guaranteed.
foundation pitcombined supporting systemcounterweight soilinclined bracemechanical behavioroptimization design
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