高压旋喷玻纤筋锚索在基坑支护工程中的应用

Application of high-pressure jet grouting anchor cable with GFRP in foundation pit support engineering

介绍了一种新型大直径全粘结型锚索即高压旋喷玻纤筋锚索的结构、特点及成锚机理。以武汉市某深基坑工程为例,通过现场抗拔试验及支护结构变形监测,对高压旋喷玻纤筋锚索的适用性、安全性及破坏模式等进行了研究。结果表明:高压旋喷玻纤筋锚索用于存在一定厚度填土层的地层时,承载力可以满足设计要求,从而解决基坑支护工程中采用普通锚杆长度过长的问题;高压旋喷玻纤筋锚索的破坏过程可分为弹性变形、弹塑性变形、塑性变形三个阶段。在弹性变形、弹塑性变形、塑性变形阶段的荷载-位移曲线分别呈线性、二次函数型、指数型。高压旋喷玻纤筋锚索的界面抗剪刚度是限制其使用的一个重要因素。

The structure, characteristics and anchoring mechanism of a new type large-diameter fully bonded anchor cable, namely high-pressure jet grouting anchor cable with glass fiber reinforced polymer(GFRP) were introduced. Taking a deep foundation pit project in Wuhan as an example, the applicability, safety and failure mode of the high-pressure jet grouting anchor cable with GFRP were studied through on-site pull-out tests and deformation monitoring of support structure. The results show that when the high-pressure jet grouting anchor cable with GFRP is used in the stratum with a certain thickness of the fill layer, its bearing capacity can meet the design requirements, so as to solve the problem of the excessive length of the ordinary anchor rod in the foundation pit support project. The failure process of the high-pressure jet grouting anchor cable with GFRP can be divided into three stages: elastic deformation, elastic-plastic deformation and plastic deformation. The load-displacement curves of elastic deformation, elastic-plastic deformation and plastic deformation stage are linear, quadratic function type and exponential type respectively. The interface shear stiffness of the high-pressure jet grouting anchor cable with GFRP is an important factor limiting its use.