太原市地层空间异质性对地面沉降分布的影响

对比1956～2000年太原市地下水位与地面沉降资料发现，该区地面沉降漏斗与地下水位降落漏斗的空间分布基本相近，但不完全吻合，局部地区存在偏移。通过对黏性土层累计厚度分布、黏性土层与粗颗粒土层的组合特征、不同分区各深度处土的力学特征值与上述偏移的对比分析，认为太原市地层的空间异质性对地面沉降分布有如下影响：（1）与地下水位降落漏斗相比，地面沉降漏斗偏向于黏性土层较厚的一侧；（2）地层组合（黏性土的夹层数、单层厚度等）对地面沉降的空间分布影响较大，沉降多发生在黏性土夹层多、单层厚度较小的地区；（3）土的力学性质的差异是影响沉降分布的重要因素。

Effect of strata heterogeneity on spatial pattern of land subsidence in Taiyuan City

Land subsidence has caused serious and costly damage to the Taiyuan City.Some previous researches attributed the problem to excessive withdraw of groundwater.However,the explanation was challenged by the noncoincidence of the spatial patterns between land subsidence and groundwater exploitation.The monitoring data in the period of 1956-2000 show that the land subsidence spatially coincides with the groundwater depression on the whole,but deviates locally.In the present study,spatial heterogeneity of medium is used to explain the phenomena.The following factors are taken into account: patterns of accumulated clay soil thickness,configurations of clay soils and coarse soils,and mechanical properties of soils in different sub-zones and depths.It is found that:(1) the land subsidence centers deviate from the corresponding groundwater depression centers to the sides with thicker accumulated clay soils;(2) in the same intensity of groundwater withdraw,the subsidence volume is usually greater where clay interbeds are more and the individual interbed is thinner;and(3) the land subsidence is correlated closely with the mechanical properties of soils.