基坑工程地下水回灌技术基本特性的研究

Study on Basic Characteristics of Groundwater Recharge Technology in Foundation Pit Engineering

当前深基坑工程开发不断增多,基坑降水引起的坑外沉降问题受到重视,地下水回灌技术作为有效的控制措施被广泛应用。在软土富水复杂地层条件的天津地区,许多学者进行了深入的研究。对天津某场地回灌过程进行水位监测和变形监测,综合研究了回灌工程的基本特性。结果表明,渗透系数会随着回灌量增大显著减小;而由于渗透性变弱后孔隙水压力会向竖向方向进行消散,发生由水压力增大而引发的水力劈裂破坏,并得到了水力劈裂计算方法;回灌可使地表和地层发生明显的隆起,因此可以有效控制沉降的发生;土层竖向变形呈现下大上下的趋势,水平变形呈现外凸模式。

With the development of deep foundation pit,the settlement outside the foundation pit caused by foundation pit dewatering has been paid more attention,and groundwater recharge technology has been widely used as an effective control measure.Many scholars have done in-depth research in Tianjin,where soft soil is rich in water and complex stratum conditions.Water level monitoring and deformation monitoring are carried out in the recharge process of a site in Tianjin,and the basic characteristics of the recharge project are comprehensively studied.The results show that the permeability coefficient decreases significantly with the increase of the recharge amount,and the pore water pressure dissipates vertically after the weakening of permeability,resulting in hydraulic fracturing failure caused by the increase of water pressure,and the calculation method of hydraulic fracturing is obtained.Recharge can make the surface and stratum heave obviously,so the subsidence can be controlled effectively.The vertical deformation of soil layer presents a trend of upward and downward,while the horizontal deformation presents a convex pattern.