深基坑桩锚支护体系变形特性研究

以西安市高新区某深基坑为例,选取周边环境较为复杂的基坑北侧为对象。分别对基坑护坡桩的桩身水平位移、锚索拉应力进行全程监测、分析。结果表明:桩后土体受间歇性降雨的作用,会引起护坡桩的桩身水平位移值的较大波动,对桩锚结构的支护能力产生影响;设置在含黏性土、有机质成分较高的土层中的锚索,容易产生较大的岩土体蠕变,进而引起锚索拉应力松弛;预应力锚索在该工程的一定程度上起到预警作用,桩锚体系支护作用的效果显著。监测结果验证了该基坑支护体系设计的可靠性与合理性。

Study on Deformation Characteristics of Pile-anchor Supporting System for Deep Foundation Pit

Taking a deep foundation pit in High-tech Zone of Xi’an City as an example,this paper selected the northern side of the pit,where the surrounding environment is complex,as the object,then made the supervision and analysis on the horizontal displacement of the retaining piles and the tensile stress of the anchor cable,respectively.The results show that the soil mass behind the piles,under the action of intermittent rainfall,will bring about large fluctuation in the horizontal displacement value and then make impact on the supporting capability of the pile-anchor structure the anchor cables,which are set in the soil strata with rich content of clay and organic matters,give rise to large creep of rock and soil mass easily,further leading to relaxation of the tensile stress therein the prestressed cable,on a certain extent,plays a role of early warning in this project,and the pile-anchor system a role of bracing significantly.The supervision result verifies the reliability and reasonability of the supporting design for the foundation pit.