无降水深基坑抗浮锚杆-旋喷体封底阻水体设计

Design of sealing bottom water-stop body of anti-floatage anchor-jetting body in non-dewatering deep foundation pits

基坑降水是基坑土方开挖阶段和使用阶段的重要环节,但会打破原有的地下水平衡,严重浪费地下水资源,并引起不均匀沉降,导致了较多的工程事故。抗浮锚杆-旋喷体是新型无降水深基坑底部的重要止水结构。基于无降水深基坑抗浮锚杆-旋喷体力学分析、阻水体有效性、支护体系安全,确定了旋喷体处于弹性工作状态,应用弹性力学理论建立了均布荷载、集中荷载作用下的弹性厚板应力解,得到了旋喷体的强度安全控制方法和抗浮锚杆的抗拔力计算方法,并开发设计软件用于某深基坑的抗浮锚杆-旋喷体封底阻水体的设计,基坑施工监测数据表明：在基坑土方开挖和使用阶段,基坑内除少量侧壁渗水和自然降水外,基坑安全性满足施工和使用要求。

The dewatering work of foundation pits is an important part of foundation pit engineering. Because this work may break the original balance of groundwater, and cause uneven settlement of the surrounding ground surface, and serious engineering accidents. At the same time, it wastes groundwater resources seriously. The anti-floatage anchor-jetting body（AAB） of deep foundation pits is a new important sealing structure of non-dewatering deep foundation pits. Based on the analysis of the mechanics of AAB in non-dewatering deep foundation pits, the effectiveness of the water-stop body and the safety of the support system, it is determined that the jetting body is in the elastic state. Using the theory of elasticity, the stress solutions of elastic thick plate under uniform and concentrated loads are established, the strength safety control method and the relevant method for calculating anti-uplift force of anti-floatage anchor are obtained, and the software for the design of sealing bottom water-stop body of AAB in non-dewatering deep foundation pits is developed. The monitoring data of foundation pit show that, in the excavation and service, the safety of the foundation pit meets the requirements of construction, although it has a small amount of side wall seepage and natural watering.