中国大陆浅层地壳实测地应力分布规律研究

RESEARCH ON DISTRIBUTION RULE OF SHALLOW CRUSTAL GEOSTRESS IN CHINA MAINLAND

通过收集中国大陆地区450多个钻孔的地应力实测资料,筛选出受局部因素影响小的450组数据,建立我国垂直应力、最大和最小水平主应力随埋深的分布变化图,研究其变化趋势,并与全球的回归结果进行对比;建立我国最大水平主应力与最小水平主应力之比随埋深的散点分布图,分析水平应力的差异性以及其沿埋深的变化规律;鉴于最大和最小水平主应力的差异大,尤其是在浅部,用最大水平主应力与垂直应力之比更能反映水平构造应力的作用,改进Hoek和Brown用平均水平应力与垂直应力之比进行统计分析的方法和形式,建立我国最大水平主应力与垂直应力之比、最小水平主应力与垂直应力之比随埋深的散点分布图,并进行相应的回归分析。上述统计分析系统总结我国大陆地区地应力场的分布规律,部分统计形式为新的尝试,可为中国地应力场的宏观分布特征研究及相关行业的工程建设提供参考。

Through collecting the measured geostress data from about 400 drillings up to now in China mainland, 450 groups of data with less local influence are selected. The trend of the vertical stress, the maximum and the minimum horizontal principal stresses with depth are established; and the results are compared with the world-wide corresponding regression analysis results. The dispersed point charts of ratios of the maximum and the minimum horizontal principal stresses varying with depth in China are established; and the change rules of the ratios with the depth are studied. As the difference between the maximum and the minimum horizontal principal stresses is great, especially in shallow positions, the ratios of the maximum horizontal stresses to the vertical stresses reflect the horizontal tectonic stress better than the average horizontal stress. The geostress statistic analysis method of Hoek and Brown, which uses the ratio of the average horizontal stress to the vertical stress to study the change rules of geostress with depth, is improved. The dispersed point charts of the ratio of the maximum horizontal stress to the vertical stress and the ratio of the minimum horizontal stress to the vertical stress with depth in China are established; and the corresponding regression analysis is also done. The distribution rules of geostress in China mainland is systematically summarized; some statistic forms are used firstly; and the research results can provide references to the study of macroscopic distribution characteristics of geostress in China mainland and for engineering constructions of related industries.