深基坑双排桩加锚索支护结构的力学特性及变形分析

Mechanical Characteristics and Deformation Analysis of Double-Row Piles with Anchor Cable Support Structure in Deep Foundation Pits

摘要: 深基坑中双排桩加锚索支护结构凭借协同承载效率高、变形控制效果好的优势，在深基坑等岩土工程中得到广泛应用，其变形与力学响应规律是保障工程安全与设计优化的关键。为精准揭示该结构在复杂岩土环境中的工作机制，本文采用Midas GTS NX软件开展数值模拟研究，构建贴合工程实际的三维力学模型，将单排锚索精准布置于双排桩缝隙处，充分耦合桩–土–锚索的非线性相互作用，实现对支护体系的精细化分析。研究表明：前排桩主要承担外侧岩土体的主动土压力，后排桩通过协同受力限制整体变形，桩身水平位移呈“中间大、两端小”的抛物线分布；锚索轴力沿锚固长度从自由段向固定段逐步衰减，缝隙中布置的单排锚索可有效协调双排桩的变形差，显著提升结构整体刚度；结构变形与力学响应受桩间距、锚索预紧力、桩身刚度及岩土体物理力学参数的综合影响，其中锚索预紧力对控制水平位移的敏感性最高。研究所得的变形特性与力学规律具有普遍性，可为同类支护结构的工程设计与施工提供科学参考，进一步验证了Midas GTS NX在特定布置形式支护结构数值模拟中的应用价值。

Abstract: Double-row piles with anchor cable support structure in deep foundation pits have been widely used in geotechnical engineering such as deep foundation pits due to their advantages of high collaborative bearing efficiency and excellent deformation control performance. Its deformation and mechanical response laws are the key to ensuring engineering safety and design optimization. To accurately reveal the working mechanism of this structure in complex geotechnical environments, numerical simulation is carried out using Midas GTS NX software in this paper. A three-dimensional mechanical model consistent with actual engineering conditions is established, in which a single row of anchor cables is precisely arranged in the gap between double-row piles. The nonlinear interaction of pile-soil-anchor cable is fully coupled to realize refined analysis of the support system. The results show that the front-row piles mainly bear the active earth pressure of the outer rock and soil mass, while the rear-row piles restrict the overall deformation through collaborative stress. The horizontal displacement of the pile body presents a parabolic distribution of “large in the middle and small at both ends”. The axial force of the anchor cable gradually attenuates from the free section to the fixed section along the anchorage length. The single row of anchor cables arranged in the gap can effectively coordinate the deformation difference between double-row piles and significantly improve the overall stiffness of the structure. The structural deformation and mechanical response are comprehensively affected by pile spacing, anchor cable pre-tightening force, pile stiffness and physical and mechanical parameters of rock and soil mass, among which the anchor cable pre-tightening force has the highest sensitivity to controlling horizontal displacement. The obtained deformation characteristics and mechanical laws are universal, which can provide a scientific reference for the engineering design and construction of similar support structures, and further verify the application value of Midas GTS NX in the numerical simulation of support structures with specific layout forms.