大型基坑降水工程弱透水层水文地质参数的计算

弱透水层的水文地质参数,对于基坑降水和地下结构的设计都是不可缺少的重要指标。但由于渗透性较差,在抽水试验中的抽水井持续很短时间就疏干,因此对于渗透性较弱的透水层水文地质参数的正确求取存在很大的困难。本文以长春市宏亿数码广场基坑降水求参过程为例,在进行了多次短时间的抽水试验后,利用所得数据采用了传统的地下水动力学求参公式和全程曲线拟合法对目的含水层进行参数的求取。然后利用Visual Modflow软件,建立了合理的渗流计算模型,通过观测水位数据对所求参数进行修正,不断调整模型中的水文地质参数,使模拟流场与实际流场拟合,从而得到更接近于实际情况的水文地质参数,取得了良好的效果。

Calculation of hydrogeological parameters of the aquitard for dewatering engineering of large foundation pit

The hydrogeological parameters of the aquitard are the important indices for the design of the dewatering and underground structure. With the weak permeability the pumping well is drained in short time when doing pumping test. It is very difficult to get the accurate parameters of the aquitard with the common methods. Taking the dewatering engineering of Changchun Hongyi digital plaza as the example,after the many short-time pumping tests,the parameters are calculated by the traditional groundwater dynamical formula and the whole curve-matching method,and the reasonable seepage simulation model for groundwater is developed by using software Visual Modflow. Through the observation data of the groundwater level,the obtained parameters from the calculation are modified, and the modified parameters are adjusted continuously,which make the simulated flow field fit the measured one. The hydrogeological parameters that are coincide to the field conditions are obtained,which get the satisfied effects.