宝鸡市渭北台塬马兰黄土震陷特性研究  

A study of loess seismic subsidence of tableland to the north Weihe River in Baoji City

作　　者：郭乐[1] 王家鼎[2] 谷天峰[2] 

机构地区：[1]铁道第三勘察设计院集团有限公司,天津300251 [2]西北大学地质学系,大陆动力学国家重点实验室,西安710069

出　　处：《水文地质工程地质》2012年第2期61-65,共5页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金(40972193)

摘　　要：以宝鸡市地震小区划为依托,选取渭北典型黄土台塬场地,采集大量不同深度(1m、3m、5m)原状马兰黄土样品进行动三轴震陷试验,研究不同深度黄土震陷变化规律。建立了震陷曲线数学模型,分析表明,震陷基本参数起始动应力受含水量影响最显著,随含水量增加而减小,临界动应力与极限动应力受含水量影响不明显,但含水量大于塑限后随含水量增加而减小。震陷基本参数与孔隙比呈负相关关系,存在一特征孔隙比,当大于该特征孔隙比后,震陷临界动应力和极限动应力随孔隙比增大而迅速减小。提出一种表征震陷敏感性的指标———震陷敏感性系数Sc,反映震陷发生难易程度,其随含水量的增加而增大,随孔隙比的增加而增大。With the support of the Baoji City seismic zonation project, a typical loess tableland site is selected and sufficient undisturbed loess samples at different depths （lm, 3m, 5m） collected. Based on the establishment of mathematical function model of seismic subsidence curves, basic parameters have been studied. The initial dynamic stress is affected significantly by and decreases with water content. The critical and ultimate dynamic stress is not sensitive to water content but decreases when it is greater than the plastic limit. The basic parameters show a negative relationship with void ratio, and there exists a critical one; as void ratio is larger than that, the critical and ultimate dynamic stress reduce significantly as void ratio increases, A seismic subsidence indicator, sensitivity coefficient, is proposed to reflect the vulnerability, and the indicator grows with the increase in both water content and void ratio.

关 键 词：台塬马兰黄土 震陷 动三轴试验 震陷敏感性系数 

分 类 号：P642.131[天文地球—工程地质学] TU411.8[天文地球—地质矿产勘探]