直排式真空预压法在天津港地基处理工程中的应用

真空预压法是目前沿海地区新近吹填土地基加固处理的主要方法,但近年来因资源紧张,用作水平排水通道的中粗砂价格不断上涨,致使工程投资大幅增加,甚至导致被迫停工,造成很大损失。直排式真空预压法在对传统真空预压法施工工艺优化的基础上,将排水板直接与滤管相连,通过缩短真空压力的传递路径以降低能耗,已取得预期的加固效果。相关理论计算和工程实践均表明,直排式真空预压法不受砂垫层的制约,造价低、能效高、工期短,前期沉降速率大,固结度、沉降速率和十字板抗剪强度等检测指标均满足要求。

Application of Direct Vacuum Preloading Method in Tianjin Port Foundation Treatment

At present, vacuum preloading method is mainly applied for reinforcing foundation formed by dredger fills in coastal area. When soft deposits are reinforced by the method, medium coarse sand is used to be horizontal drainage channel. In recent years, its price rises continuously due to the shortage of medium coarse sand resource, which causes higher cost of the projects, even shutdown of the project with unacceptable loss. By optimizing conventional vacuum preloading construction technology, direct vacuum preloading method is adopted to connect drainage board with filter tube directly, shorten vacuum transfer path and reduce energy consumption. The predicted effect is obtained. The relevant theoretical calculation and project example show that direct vacuum preloading method is not restricted by sand bed, which is characterized with low cost, high efficiency, short construction period and high settlement velocity in early stage. In addition, the consolidation degree, settlement velocity and vane-shear strength indexes satisfy the design requirements.