湘潭市某深基坑复合土钉墙支护变形的有限元分析

Finite Element Analysis of Composite Soil Nailing Wall Deformation for Deep Excavation in Xiangtan

复合土钉墙在基坑中应用广泛,目前对其变形的研究较少.本文依托湘潭市河西核心商务区人防平战结合工程,运用有限元分析软件ANSYS建立微型桩-预应力锚杆复合土钉墙与纯土钉墙两种不同支护形式在不同工况的有限元模型,得到各开挖步基坑的变形情况,将有限元计算结果与现场实测数据进行对比分析.结果表明:由于受到土体主动土压力作用,微型桩产生微小转动,复合土钉墙支护水平位移呈现开挖面以上与以下相反的现象,在基坑顶部有较小幅度的土体拱起,微型桩和预应力锚杆的施加对基坑侧壁水平位移与地面沉降有较大影响,能有效控制土体变形,增加土体稳定性,但是对坑底隆起的影响相对较小.

Composite soil nailing wall has been widely used in deep excavation structure,but research on the deformation of feature is still relatively less.Based on the back ground of specific engineering,the paper compared and analysed the different supporting structure between micro pile pre-stressed anchor composite soil nailing and pure soil nailing on different forms,established the finite element model,and got deformation on different condition,compared the finite element results with the measured data.The results show that：due to the effect of active earth pressure,micro piles produce tiny rotating,the horizontal displacement of composite soil nailing shows the opposite phenomenon above the excavation face and the following,the top of micro pile has a smaller uplift,applied in excavation sidewalls micro piles and pre-stressed anchor have a greater impact to the horizontal displacement and the ground settlement,and can effectively control soil deformation,increase soil stability,but the impact to pit bottom uplift is relatively smaller.