Hoek—Brown强度参数取值及水电工程应用方法对比研究

COMPARATIVE STUDY ON TWO METHODS OF ROCK MASS STRENGTH PARAMETERS FOR APPLICATION IN HYDROPOWER ENGINEERING

岩体强度和地应力之间的矛盾导致的应力型破坏在我国西部水电开发过程中比较普遍地出现,岩体强度参数取值因此成为西部水电工程实践中重要的环节之一,直接影响着工程问题的解决方案。针对我国水电行业岩体取值方法所考察因素与Hoek—Brown方法的差异,本文在论述岩性、围压条件、岩块破损对岩体强度参数取值影响的基础上,重点讨论了水电经验取值方法与Hoek-Brown经验取值方法的差异及其在西部复杂条件下的适用性。结论如下:(1)岩性、围压水平和破损特性对强度参数的影响不容忽视;(2)水电经验取值方法适用于低围压条件,在西部水电工程中适用性相对较差;(3)HoekBrown经验取值方法同时考虑了岩石材质、围压效应和破损效应的影响,既能实现中东部地区水电工程岩体力学参数取值经验的延续,也适用于西部水电工程的高应力环境和复杂地质环境。

Stress-induced failure of rock mass due to the conflicts between rock mass strength and relatively high in-situ stresses,has commonly occurred during the developments of hydropower projects in western China. Estimates of rock mass properties have thus become one of the important tasks in the engineering practice,which can have significant influence on decision-making for engineering problems. This paper examines the differences of considerations in two empirical methods of the Hydro- engineering approach and the Hoek—Brown method. It addresses the influences of three main factors on rock mass strengths. They include lithology,confinement level,and damage of intact rock. Then,it examines the applicability of the two empirical approaches to the condition where the three parameters soundly present. The findings suggest that（ 1） the influence of these three factors cannot be ignored on estimating rock mass properties;（ 2） the Hydro-engineering approach is applicable to low-stress conditions whereas less suitable in western area where stress appears relatively high;（ 3） the Hoek—Brown method is applicable to both circumstances,i.e.,low stress condition typically in the areas of central and eastern China aswell as complex geological conditions with high in-situ stresses represented with the area of western China.