半干旱矿区近浅埋煤层开采潜水位恢复预测  

Prediction of groundwater table recovery affected by approximate shallow buried coal mining in semiarid region

作　　者：李涛[1] 李文平[1,2] 孙亚军[1,2] 

机构地区：[1]中国矿业大学资源与地球科学学院,江苏徐州221116 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221008

出　　处：《中国矿业大学学报》2011年第6期894-900,共7页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2007CB209401)

摘　　要：为剖析半干旱矿区近浅埋煤层开采基本不渗漏区潜水位恢复机制,通过物理相似模拟揭示了煤层开采造成的潜水位降深呈"降落漏斗"状,建立了潜水位恢复的单井数学模型,在修正的Theis公式的基础上对潜水位恢复时间进行了预测,并将解析计算、模型试验及实测结果进行对比检验.最后分析了潜水位恢复动态规律及其对地质环境的影响.结果表明:基本不渗漏区域煤层回采造成砂层水位骤降,其瞬时水位可近似看作虚拟抽水产生的降落漏斗,而其恢复过程可视为停止虚拟抽水的水位恢复过程.水位恢复停采时降深95%的解析恢复时间为225d,比物理模型试验所得时间300d略小,其误差主要源于井函数的近似取值和采空区上覆岩土层非连续塌陷.工作面附近泉水流量的实测曲线显示数学模型的误差为9.1%;依此预测出潜水位在初期恢复较快而后期恢复缓慢,将造成农业短期大面积减产、植被可逆性退化及土地沙化缓解等地质环境效应.In order to analyze the mechanisms of groundwater table recovery in non-leakage of semiarid mining areas with approximate shallow buried coal mining,physical simulation tests were carried out to observe the drawdown which was confirmed to be of ＂cone of depression＂ shape.A single well mathematical model of dive recovery was set up based on the law of mining drawdown characters and then solved to predict the recovery time based on modified Theis equation.The results of the mathematical model were checked and compared with the results of the recovery time of physical model and measured flow of springs.The law and influence on geological environment of groundwater recovery were then analyzed.The results show that the approximate shallow buried coal mining resulted in instantaneous decline of water level,and regarded the symmetrical cone of depression by virtual pumping at a constant rate and the water recovery as the consequence after virtual pumping.Because of the rock and soil collapse in goaf as well as calculation error from the value of well function approximation,the recovery times of both mathematical and physical models needed 225 d and 300 d respectively,when the groundwater recovery reached 95% of the drawdown after mining.The error of mathematical model was 9.1% as checked by the measured flow curves of springs near to the working face.Groundwater table recovery was quick in early stage but slowed in later stage and this led to reduction of crop yields in the large area during early stage,degeneration of vegetation reversibility and remission of land desertification.

关 键 词：保水采煤 水位恢复 单井数学模型 泰斯公式 误差 地质环境 

分 类 号：P333.5[天文地球—水文科学]