蚀变岩工程分级与物理力学性质研究

STUDY ON ENGINEERING CLASSIFICATION AND PHYSICAL AND MECHANICAL PROPERTIES OF ALTERED ROCK

在岩石工程中,蚀变作用通常会引发各种工程地质问题。以新疆北部某深埋长隧洞中蚀变岩为对象,研究了蚀变岩的微观特征和物理力学性质,并对蚀变岩隧洞段进行了数值模拟。结果表明岩石蚀变类型为黑云母的绿泥石化和钾长石的黏土化,利用蚀变岩中绿泥石含量与黏土矿物含量提出了蚀变指数概念,并结合蚀变岩的宏观表观特征,对其进行蚀变程度分级。随着蚀变程度的增加,岩石的吸水性、孔隙率随之变大,块体密度、饱和单轴抗压强度、弹性模量、变形模量大幅度降低。工程实例模拟发现,随着岩石蚀变程度的增强,隧洞围岩位移明显增大,揭示了蚀变作用对围岩变形破坏有很大影响。研究成果对蚀变岩地区类似工程具有一定的参考价值。

In rock engineering,alteration usually causes various engineering geological problems.The microscopic characteristics and physical and mechanical properties of altered rocks in a deep buried long tunnel in northern Xinjiang were studied,and numerical simulations were performed for the altered rock tunnel section.The results show that the rock alteration type of the tunnel surrounding rock is chloritization of black mica and clayification of potassium feldspar.The concept of alteration index is proposed using the chlorite content and clay mineral content in the altered rock.The macroscopic characteristics of the altered rock are combined to classify the alteration degree.As the degree of alteration increases,the water absorption,and porosity of the rock subsequently become larger,and the bulk density,saturated uniaxial compressive strength,elastic modulus,and deformation modulus decrease substantially.The engineering example simulation found that the displacement of tunnel surrounding rock is increased significantly with the enhancement of rock alteration,revealing that the alteration effect has a great influence on the deformation and damage of surrounding rock.The research results have a certain reference value for similar projects in eroded rock areas.