富水软弱地层双排桩深基坑力学特性研究

Study on mechanical characteristics of deep foundation pit with double-row piles in soft strata with rich water

以某深基坑工程实例为依托,通过双排桩-锚杆支护体系受力特性的现场试验,研究了不同开挖工况下双排桩桩身内力、桩顶位移、土压力、土体深层位移、锚杆内力等变化规律,为双排桩-锚杆支护结构的设计提供参考依据。基于现场工况,建立了双排桩-锚杆支护结构的三维有限元模型,分析了双排桩-锚杆支护结构的力学响应规律。结果表明:桩顶位移和土体深层位移均远小于规范限制位移,对于黄河冲积地层下的深大基坑工程,双排桩-锚杆支护结构具有较好的支护效果;在设置锚杆的状况下,前排桩的弯矩呈S形,后排桩的弯矩呈抛物线形;桩后土压力受开挖深度和时间效应的共同影响显著。

Relying on a deep foundation pit engineering example,this study presents systematic field tests to investigate the stress characteristics of a double-row pile-anchor support system,which delves into the variations in internal force,pile top displacement,earth pressure,deep soil displacement,and anchor rod internal force of double-row piles under different excavation conditions,thus providing references for the design of the double-row pile-anchor support structure.At the same time,a three-dimensional finite element model of the double-row pile-anchor support structure is established based on on-site conditions,yielding insights into the mechanical response of this system.The results show that the pile top displacement and deep soil displacement are much smaller than the standard limit displacement,demonstrating the effective support provided by the double-row pile-anchor support structure for deep and large foundation pit projects,especially in alluvial strata of the Yellow River.Furthermore,in the case of setting anchor rods:the front row pile exhibits an S-shaped bending moment,while the rear row pile follows a parabolic pattern.The post-pile earth pressure is significantly affected by the combined effect of excavation depth and time.