摘要
对原地应力状态的准确把握是地下工程稳定性评价的重要基础,而选择可行的高地应力判据是进行地应力状态评价的前提条件。在详细分析现有各种原地应力评价判据的基础上,提出可行的高地应力判据,并在判据模型中引入了国际上认可度非常高的Shoerey模型,但该模型没有考虑岩体变形模量和岩石弹性模量的区别。通过广泛研究目前国内外关于岩体强度的理论和方法,引入Hoek-Brown岩体强度估算理论,补充完善了Shoerey模型。云南禄丰某工程隧道,工程区共布置两个地应力测孔,测试结果较为离散。利用应力状态评价和数据拟合方法,推算出最大埋深部位的应力值达19.29 MPa,而岩体整体强度仅为5.243 MPa。按照强度应力比和Shoerey模型的评判标准,该隧道洞身部位的应力状态均为极高应力状态,应引起重视。对原地应力状态评价的一般方法和步骤进行了概括总结,以方便其他工程参考使用。
To define the in-situ stress regime accurately is one very important basis for stability design and evaluation of underground project. By analyzing how to evaluate the in-situ stress state in the past, it is found that many used methods have totally different standards and criterions in China, and one new high stress criterion and analysis method is established by reference to the past findings. Here the internationally-widely-accepted Shoerey＇s model is introduced into the modified high stress criterion; but this model does not take the difference between deformation modulus of rock mass and Young＇s modulus of intact rock sample into consideration. For this reason, the authors introduce the deformation modulus from Hock-Brown criterion into this model to better the Shoerey＇s theory, and form the modified Shoerey＇s model. A tunnel in Lufeng County, Yunnan Province, has burial depth up to 525m, the lithology of surrounding rock mass is sandy slate. Two boreholes, ZK5 ＆ ZK9 for hydro-fracturing in-situ stress measurement, are arranged along the tunnel line, but the measurement results are rather scattered. The in-situ stress magnitude at the tunnel section, estimated with the methods suggested by this paper, is up to 19.29 MPa; but the global strength of rock mass is only about 5.243 MPa. According to the strength-to-stress ratio method and the criterion from modified Shoerey＇s model, the tunnel section at the largest burial depth is under the high in-situ stress; and the project construction and design department should pay more attention to such a condition. Finally, the general method and procedures to evaluate the in-situ stress state are summarized to offer some references for other projects.
出处
《岩土力学》
EI
CSCD
北大核心
2009年第8期2359-2364,共6页
Rock and Soil Mechanics
基金
财政部基本科研业务专项资助项目(No.ZDJ2007-5、No.ZDJ2007-20)
国家自然科学基金青年基金项目(No.40704018)
