城市建设引发场地土变异的剪切波速试验分析

对大规模的城市建设行为,在当前振动源越来越多的情况下,总结了分析城市建设荷载的表现形式及其导致的场地土结构、性状的变化,得出场地土动力参数与剪切波速关系,测试研究场地土在不同密度、含水量、应力状态下剪切波速的变化情况,探讨了城市建设引发的场地土层动力特性变异规律,并与建筑场地打桩前后剪切波速变化的工程实例进行了对比分析。试验结果表明,地面建筑、地下工程、地下水开采等城市建设行为,造成了土体的密度、含水量以及应力变化,场地土剪切波速发生变更,引起场地土动力特性变异,整体或局部改变了建筑场地类别。建筑场地抗震设计应该适当考虑大规模城市建设引发的场地土动力特性变异对抗震参数取值的影响。

Shear Wave Velocity Test Analysis for Variation of Site Soil Initiated by City Construction

In case of large scale activities of city construction, the vibration sources become more and more, the form of the city construction loads and the change of the structure and character of site soil are summarized and analyzed, experimental study on the shear wave velocity in the state of different densities, different moisture contents and different stresses of soil, the variation law of dynamic characteristics of site soil initiated by city constructions is studied, and comparative analysis is carried out on engineering example for the changes of shear wave velocity before and after driving pile. The laboratory test results indicated that, activities of city construction such as surface buildings, underground excavation and groundwater exploitation, causing the changes of site soil’s densities, moisture contents and stresses, the change of shear wave velocity would lead to variations of dynamic characteristics of site, it has in overall or locally changed the category of building site. A seismic design of building site should have proper consideration on effects of variation of dynamic characteristics of site soil initiated by large scale activities of city construction on anti-seismic parameters.