弱含水层干扰井群人工井点降水水位降深研究

Study on Water Level Subsidence Due to Interferential Well Group Dewatering in Weak Aquifer

中文关键词:弱含水层  粘土  干扰井群  影响半径

英文关键词:weak aquifer  clay  interferential well group  radius of influence

中文摘要:

      一般情况下按隔水层考虑的粘土层及粉质粘土层，由于其内部存在微结构决定的特殊地下水，在工程中需作降水处理。弱含水层的降水设计计算与富水层不同，弱含水层渗透系数远小于富水层，在其他条件相同的情况下，其影响半径也远小于富水层，故在弱含水层降水过程中出现井内动水位与基坑底面静水位相差较大的现象。在弱含水层干扰井群降水计算时，不能按各单井等涌水量考虑，且不一定所有井都对计算点水位降深产生干扰。以长春站南北广场地下通道工程为背景，提出了弱含水层干扰井群降水计算方法，即在确定对计算点产生干扰的井数基础上，考虑各井涌水量

英文摘要:

      Dewatering is necessary in silty clay and clay bed, which is regarded as water insulation layer, because of the internal special underground water. The dewatering calculation in weak aquifer differs from that in rich aquifer, with a far weaker permeability and, while other conditions being the same, with considerably smaller influence radius. During dewatering in weak aquifer, therefore, there is a large difference between the dynamic water level inside the well and the static water level under excavation bottom. The calculation cannot be accounted for according to the water inflow into each well, and it is uncertain that all wells influence the water depth decreasing. The routine calculation method usually causes larger results. On basis of the underground passage project between south and north square of Changchun Station, the dewatering calculation method for interferential well group in weak aquifer is presented. Accounting for unequal inflow of the wells, the formula is deducted for dewatering depth of interferential well group in weak aquifer based on determination of a number of wells interfering a certain point. Finally, the calculation result is compared and checked with the field survey data.