框架预应力锚杆联合微型钢管桩新型支护结构数值分析

Numerical simulation of combined retaining structure of frame pre-stressed anchors and micro steel tube piles

针对深基坑工程中场地小、周围土体松散的支护问题,将'主动'和'被动'加固思路相结合,提出了新型的联合支护体系——框架预应力锚杆联合微型钢管桩新型支护结构。本文对结构的组成和工作机理进行了详细阐述。为了探究注浆半径、支护深度比以及排桩数目对新型结构工作性能的影响,分别建立了不同影响因素工况下的有限元分析模型,对多种工况下的数值结果进行了对比分析,结果表明:注浆半径越大,新型结构对基坑的位移控制效果越好,协同性也越好;在1:2的支护深度比下,新结构的工作性能优于1:1的情况;3排桩情况下的结构力学特性优于2排。本文的数值研究对该新型结构的应用提供必要的技术支持。

In view of the small support in the deep foundation pit project and the loose support of the surrounding soil,the'active'and'passive'reinforcement ideas are combined to propose a new type of joint support system-frame prestressed anchor combined with micro steel pipe.The composition and working mechanism of the structure are elaborated in this paper.In order to explore the effects of grouting radius,support depth ratio and number of rows on the performance of the new structure,the finite element analysis model under different influencing factors was established,and the numerical results under various working conditions were compared.The analysis shows that the larger grouting radius,the better displacement control effect of the new structure on the foundation pit and the better synergy;the performance of the new structure is better under the support depth ratio of 1:2 than 1:1;the structural mechanical properties of the 3-row pile are better than those of the 2 rows.The numerical studies carried out in this paper provide the necessary technical support for the application of the new structure.