渭河盆地深部构造活动的地裂缝孕育机理

渭河盆地是我国乃至世界上地裂缝最发育、灾害最严重的地区。基于渭河盆地深部构造模式，采用有限元数值分析方法，分析了上地幔上隆、中地壳流展和上地壳拉张3种深部构造作用下盆地浅表岩土介质的应力和变形响应特征，从而揭示了渭河盆地深部构造活动与该区域地裂缝群发之间的孕育关系。结果表明：上地幔的隆起和中地壳侧向流展形成了浅部拉张应力环境，这种效应与盆地周边块体运动形成的伸展引张构造应力场叠加，再附加断裂伸展倾滑形成的局部拉伸应力场构成了地裂缝形成的主要动力来源。

Ground Fissures Germination Mechanism of Deep Structure Activities in Weihe Basin

Weihe basin is the most developed area of ground fissures and its hazard is also the most serious in China, even in the world. Based on the deep structure mode of Weihe basin, a numerical analysis with finite element method is made to study the stress and strain response of superficial ground subjected to the deep tectonization of upper mantle uplifting, middle crust lateral stretching and upper crust tension. The germination relationship between deep structure activities and ground fissures development is revealed. Results show that the tensile tress environment is formed by upper mantle uplifting and middle crust lateral stretching, which combines with stretching stress fields induced by surrounding blocks activity and faults dipslip, constitute the main motive resource of ground fissures development.