不同地质成因岩石地应力分布规律的统计分析

通过收集我国大陆地区大量的实测地应力资料,筛选出了受局部影响小的实测数据,建立了岩浆岩、沉积岩和变质岩地应力随埋深分布的散点图,并根据各自的分布规律进行了相应的回归分析.结果发现,三大类岩石的地应力分布规律存在差异,其主要与岩石地质成因相关.三大类岩石的垂直应力总体上随埋深呈线性增大,量值接近各自上覆岩层自重;最大水平主应力随埋深均呈线性增大,相同埋深条件下,火成岩量值最大,变质岩次之,沉积岩最小;而沉积岩浅部最小水平应力大于岩浆岩;三大类岩石的水平差应力总体上随埋深也呈线性关系,相同埋深条件下,火成岩较大,而沉积岩较小;浅部岩浆岩平均水平主应力与垂直应力之比最大,而沉积岩较小.

Statistical analysis of geostress distribution laws for different rocks

Through collecting a vast amount of the measured geostress data in Chinese mainland as so far and selecting the data which has less local impact, the geostress trend pictures with depth of magmatic rocks, sedimentary rocks and metamorphic rocks are established and the corresponding regression analysis is conducted according to the respective distribution laws. The research results show that the distribution characteristics of three kinds of rocks are different, which mainly result from the different formed mechanisms. The vertical stress is linearly increased with depth for the three kinds of rocks. The vertical stresses of all rocks nearly equal to the weight of respective overburned rocks. The maximum horizontal principal stress is also linearly increased with depth for the three kinds of rocks. Under the same depth, the maximum horizontal principal stress of magmatic rocks is maximum; sedimentary rocks middle and sedimentary rocks minimum. At the shallow depth, the ratio of the average horizontal stresses and the vertical stresses of magmatic rocks are maximum, and the ratio of metamorphic rocks is minimum. The statistic analysis results above can be useful references for the study of the macro stress field distribution and related professions.