采水地面沉降时空预测模型研究

Space-time predicting model research of surface subsidence caused by groundwater exploitation

地下水开采引起的地面沉降对地面建(构)筑物的正常使用和结构安全构成了严重威胁,深入研究采水地面沉降预测理论对于沉降灾害防治具有重要意义。针对本构模型和土体参数确定上的困难,采用力学推理和数学统计相结合的方法,建立了新的采水地面沉降时空预测模型。首先,利用太沙基固结微分方程,建立了反映地面沉降时间效应的半经验计算模型;其次,在分析采水地面沉降空间分布规律的基础上,利用随机介质理论研究了采水地面沉降空间分布特征;再次,综合考虑采水地面沉降的时间效应和空间分布形态,建立了采水地面沉降的时空预测模型。利用该模型计算地面沉降共需4个计算参数,介绍了参数求解方法。最后,利用时空计算模型预测了某地单井采水引起地面沉降的时空规律。研究表明,所建立的采水地面沉降预测模型能准确地反映采水地面沉降的时空规律,能方便、快捷地预测地下水开采引起的地面沉降。

Land subsidence caused by groundwater exploitation seriously threatens normal employment and structure safety ot buildings, so it is of significance that studying predicting method of land subsidence. Because of the difficulty of the constitutive model and the parameters of soil, and it is not perfect that the land subsidence is computed adopting Biot＇s consolidation theory. In the paper, adopting combining methods both mechanics reasoning and statistic mathematics, sets up space-time predicting model research of surface subsidence caused by groundwater exploitation. Firstly, by means of Terzaghi＇s consolidation differential equation, the semi-experience predicting model of depicting surface subsidence＇s time effect is founded. Secondly, on the basis of analyzing the distribution laws of surface subsidence caused by groundwater exploitation, the space distribution characteristic of surface subsidence caused by groundwater exploitation is studied through the stochastic medium theory. Thirdly, synthetically analyzing the time effect and space distribution characteristics of surface subsidence caused by groundwater exploitation, the time-space predicting model of surface subsidence caused by groundwater exploitation is established. The predicting model totally needs 4 parameters when it finishes prediction. The method of parameters＇ computation is introduced. Lastly, the time-space laws of surface subsidence caused by single well＇s exploitation is computed and predicted with the predicting model. The research shows that the predicting model can nicely reflect the time and space characteristics of land subsidence caused by groundwater exploitation, and can expediently and rapidly predict land subsidence; and provides theoretical basis for prevention and control of surface subsidence caused by groundwater exploitation.