【摘要】 通过现场爆破试验,对地震动诱发条件下黄土场地震陷的监测结果进行模拟,分析爆破模拟地震动导致的黄土场地震陷的分布、发展特征及其影响因素。监测期间,试坑内黄土震陷量最大值达33 mm,试坑周围场地黄土震陷量最大值为26 mm。受地貌因素等制约,试验场地的黄土震陷具有自南向北逐渐衰减的特征。研究结果表明,微差爆破后,试验场地震陷量即接近监测完结时黄土震陷量的50%。这说明,爆破模拟地震动能使黄土场地发生震陷,黄土震陷在爆破能量传播时会快速累积,而在爆破之后,场地土体还将经历一个相对缓慢的沉降过程。该试验对地震动作用下黄土场地震陷基本特征的研究和对室内试验与现场监测获得的震陷性之间差异的理解具有一定的指导意义;同时也可丰富经验性爆破地震动强度设计的理论。更多还原

【Abstract】 Based on in-situ monitoring data of seismic subsidence of loess induced by a short delay blasting,the distribution and development of seismic subsidence and their influencing factors in a loess site are studied.The observation results show that,during the whole experiment,the maximum seismic subsidence of loess in the test site reaches 33 mm while the maximum subsidence around the site attains to 26 mm.The both maximum values of subsidence are found at the south of the test field,which depend on the landform of this loess field,but seismic subsidence of loess decreases from the south to the north.On the other hand,the results indicate that after immediate explosion,the seismic subsidence of loess developed almost 50 percent of the maximum value of final loess subsidencei,.e.during the blasting processs,eismic subsidence developed rapidly with the energy dissipation of explosives and then the increase of loess settlement in the field becomes slow and slow.According to the above-mentioned outcomes,it is believed that seismic subsidence could be induced in a loess site if there is a designed explosion with enough intensity occurring;and this in-situ test results could be an indirect example of loess seismic subsidence caused by an earthquake event in loess sites.These efforts make for a further understanding on the differences of loess seismic subsidence between laboratory and in-situ test results,and provide a basis for an empirical intensity design of explosive ground motion in practical engineering.更多还原