【摘要】 为了明确复合土钉墙的工作特性及其支护变形机理,应用离散元PFC^2D软件,根据搅拌桩、土钉及面层的物理力学特性,建立了颗粒流数值模型,分析基坑开挖过程中复合土钉墙支护时的细观工作机理,并与单一搅拌桩支护和单一土钉墙支护形式的细观工作特性进行了比较。研究发现:复合土钉墙支护的位移场和坑外地表沉降特性与单一土钉墙支护、单一搅拌桩支护相比有较大差异;在限制基坑水平位移、抗侧向变形能力和限制地表沉降方面,复合土钉墙支护要优于单一搅拌桩和单一土钉墙支护。通过对复合土钉墙的工作机理进行研究,明确了复合土钉墙支护的变形机理和影响范围,不仅可为实际工程中复合土钉墙的设计、施工和监测提供依据,也可为应用离散元方法模拟基坑工程支护特性提供参考。更多还原

【Abstract】 In order to clarify the working mechanism and deformation characteristics of composite soil nailing walls, the discrete element method（DEM） was applied based on the software PFC^{2 D}. DEM models were established for retained excavation by sheer deep-mixing-pile（DMP）, by sheer soil nail wall（SSNW） and by composite soil nailed wall（CSNW） of DMP+SN. The working mechanism of the three types of stabilization were compared by the displacement fields in soil and by the surface settlement on retained ground. It shows that the deformation characteristics within the excavated ground are quite different under the three types of stabilization, with CSN being able to mobilize deeper soil under the base of excavation to work and resulting in smaller deformations on the soil surface. In terms of limiting the horizontal displacement of excavated pits, resisting the lateral deformation and limiting the ground subsidence, the CSNW is the best choice of the three. At the same time, it can also provide a reference for the application of the DEM to simulate the support characteristics of foundation pit engineering.更多还原