深部硐室长期稳定性的两个力学问题

Mechanical problems for the long-term stability of rocks surrounding deep level underground tunnels

在陈宗基院士关于地下硐室长期稳定性力学问题研究的基础上,采用Sadovsky院士关于复杂地质岩体的等级构造学说,围绕深部岩体非均匀构造与封闭应力固有的统计力学属性,研究了岩体非均匀变形与封闭应力特性,以及深部硐室围岩的长期稳定性等两个力学问题。给出了岩体非均匀构造与封闭应力的数学表征;根据质量守恒定律得到了计算深部硐室围岩长期变形的一般公式;得到了围岩变形中劈裂扩容变形占主要部分的结论,并且阐明了深部围岩卸荷时更易出现劈裂破坏的原因。给出了劈裂破坏形态的演进序列与扩容位移的计算方法。将围岩松动圈范围、破裂区位置和边壁位移的计算结果与锦屏一级电站厂房现有监测数据进行了对比,两者相当吻合。

Based on the research of Academician Tan Tjong-Kie on the long-term stability mechanics of underground tunnel and considering Academician Sadovsky’s structural hierarchy theories on complex geological rock masses,the inherent statistical mechanical properties of inhomogeneous structure and closed stress in deep rock masses were investigated.Two mechanical problems were mainly studied,i.e.characteristics of inherent non-uniform deformation and closed stress of rock masses,and long-term stability of deep tunnels.The quantitative mathematical characterization of inherent non-uniform deformation and closed stress of rock masses were given using the method of statistical mechanics.Based on the law of mass conservation,a general calculation method of long-term stability and deformation of rock masses surrounding deep level tunnels was proposed.The Maxwell model was used to calculate the threshold of splitting.A post-peak failure model of rock was established to estimate the in-situ stress at which rock undergoes post-peak failure.With the help of the theory of the hirerachical structure of rock masses,the maximum value of rock displacement due to splitting dilatation was obtained.A dimensionless energy factor was introduced to define the extent of zonal disintegration of surrounding rock masses.It was concluded that the splitting and dilatancy deformation is the main part of the deformation of surrounding rocks.The reasons why unloading splitting failure is more likely to take place in rock masses surrounding deep level tunnels were explained.The split evolution pattern of rock masses surrounding deep level tunnels and the calculation method of dilatancy displacement were obtained.The calculation results of the range of loosening zone,the location of the rupture zone in rock masses surrounding deep level tunnels,and the displacement of the sidewall were compared with the existing monitoring data in the underground powerhouse of the JinpingⅠHydropower Station,and the agreement is good.