砂卵石地层桩锚支护结构稳定性实例研究

Case study on the stability of pile-anchor supporting structure in sandy ground

在城市中进行深基坑开挖,其稳定性至关重要。为研究砂卵石地层深基坑开挖过程中桩锚支护结构的稳定性问题,采用FLAC3D对其进行了三维模型计算分析,分析了不同开挖阶段桩锚支护体系的变形特性,以及基坑土体位移的变化情况,并与实测结果进行比较,研究了土体压力、桩体内力、锚索拉力与桩体水平位移的关系。结果表明:砂卵石地层在一定深度处存在"自立拱"效应,同时,可以对锚索进行有效的锚固,从而对桩体内力、变形起到有效的控制作用,保证基坑的稳定性。数值分析与实测结果相吻合,说明数值计算模型合理,结果可靠。

The stability and safety of deep excavations are important to urban construction.The software FLAC3D was used to assess the stability of pile-anchor supporting structure in deep excavation in sandy cobble ground.The deformation properties of pile-anchor supporting system and soil displacement of deep foundation pit during different stages were estimated numerically.Compared with in-situ monitoring data,the relationship between earth pressure,inner force of pile,tensile force of anchor cable and horizontal displacement of pile system were obtained.The results revealed that arch effect exists in certain depth in sandy cobble ground.And the sandy cobble ground is advantageous to anchored force.So they are useful to decrease the inner force and deformation of the pile system and ensure the stability of deep foundation pit.The results from field tests accorded with numerical simulations,and it showed that computational modeling was reasonable and the results were reliable.