地下水开采引起的地面沉降计算方法及分析

在Terzaghi一维固结理论的基础上结合修正的Kozeny-Carman方程,提出了适用于实际地层的、可考虑地下水类型和疏干情况及渗透系数随沉降发生变化的一维沉降计算方法。通过Fortran编写计算程序,分析了北京东南部区域的地面沉降量并与实测结果进行对比。结果表明:研究区域内在过去5年间,监测点的沉降计算结果与实测结果趋势基本一致,证明了该方法的合理性;地下水超采导致的地面沉降约占总沉降的80%;地下水类型和渗透系数均对沉降计算有影响,但地下水类型对承压水含水砂层分布较多且厚度较大的计算点的沉降计算影响较大,渗透系数对黏性土层分布较多且厚度较大的计算点的沉降计算影响较大。

Calculation Method and Analysis on Land Subsidence Caused by Groundwater Exploitation

Based on the Terzaghi one-dimensional consolidation theory and the modified Kozeny-Carman equation, a one-dimensional settlement calculation method considering the groundwater type, dewatering conditions and the variation of the permeability coefficient with the settlement that can be applied to the actual stratum was proposed in this paper. The calculation program was written by Fortran to analyze the land subsidence in the southeastern part of Beijing and the calculation results was compared with the measured results. The results showed that the subsidence calculation results of the monitoring points in the study area are basic consistent with the measured results in the past five years, which proved the rationality of the method. The land subsidence caused by over-exploitation of groundwater accounts for about 80% of the total settlement. The groundwater type and permeability coefficient both had an impact on the subsidence calculation results, but the groundwater type had a greater influence on the results of the calculation points with larger distribution and thickness of the confined water-bearing sand layer, and the permeability coefficient had a greater impact on the results of calculation points with larger distribution and thickness of the cohesive soil layer.