地应力状态与岩石力学性质的关系研究

Study on the Relationship Between In-situ Stress State and Rock Mechanical Properties

地应力是工程稳定性设计的基本参数,与岩石力学性质密切相关。根据收集到的969组地应力实测数据,对最大和最小水平主应力随深度H的变化规律进行了回归分析;并从中选取同时带有岩石弹性模量E和泊松比v的112组数据,研究了E、v与H的关系、最大和最小水平主应力分别与E、v的关系及最大和最小水平主应力与H和E的关系。结果表明,我国大陆地区最大和最小水平主应力整体上随深度增加而增大,呈线性增长关系;E与H没有明显的相关关系,随H的增加而有降低趋势;v整体上随H变化幅度较小,数据主要集中在直线v=0.23的两侧;消除深度的影响后,所选取的3个深度范围的最大水平主应力与E有一定的正相关关系,最小水平主应力与E的线性相关性较差,且出现了不一致现象,E对最小水平主应力的影响程度较小,对最大水平主应力的影响程度较大;最大和最小水平主应力总体上均随v增加有增大趋势,规律性不显著;对于最大和最小水平主应力分别与H和E的关系,修正了已有的数学模型,回归精度有所提高。

As the basic parameter of engineering stability design, the in-situ stress is closely related to the rock mechanical properties. Based on the 969 groups collected data of the actual measurement in China, the change law of the maximum and the minimum horizontal principal stress with depth （H） were analyzed by regression. 112 sets of data with rock elastic modulus （E） and poisson ratio （υ） were selected. Then, the relationship between E, υ and H, the relationship between the maximum and the minimum horizontal principal stresses with E and υ, as well as the relationship between the maximum and the minimum horizontal principal stresses with H and E were studied. The results showed that the maximum and the minimum horizontal principal stresses in the mainland of China generally increased linearly with the depth. There was no significant correlation between E and H, and E tended to decrease with the increase of H. Furthermore, υ had small changes with H, the data was mainly concentrated in the two sides of the straight line υ = 0.23. After eliminating the influence of depth, the maximum horizontal principal stress of the 3 selected depth ranges were positively correlated with E, and the linear correlation between the minimum horizontal principal stress and E was not consistent and poor. The effect of E on the minimum horizontal principal stress was small, but was relatively large on the maximum horizontal principal stress. The maximum and the minimum horizontal principal stress increased with υ in general, but the regularity was not obvious. Based on the relationship between the maximum horizontal principal stress and the minimum horizontal principal stress with H and E respectively, the existing mathematical model was modified, and the accuracy of regression had been improved.