关于土石坝心墙水力劈裂研究的一些思考

SOME IDEAS OF STUDY ON HYDRAULIC FRACTURING OF CORE OF EARTH-ROCKFILL DAM

从发生条件、力学机理、试验研究和数值模拟等方面对土石坝心墙的水力劈裂问题进行了初步探讨。研究结果表明:(1)其发生条件至少包括物质条件和受力条件两个方面;(2)力学机理可以从断裂力学的角度进行揭示,判别准则可以基于断裂力学的理论建立;(3)试验研究中试样的边界条件和受力状态能够近似模拟心墙上游面的实际情况;(4)在弄清水力劈裂的发生条件、力学机理的基础上,通过试验研究建立合理的水力劈裂判别准则,对水力劈裂的发生发展过程进行数值模拟,是研究水力劈裂问题的有效途径。

Hydraulic fracturing of core of earth-rockfill dam is an important issue related to the safety of the dam, and it attracts much attention. In this paper, the achieved results show as follows： （1） the conditions of hydraulic fracturing Should include at least two conditions＇--physical one that includes fissures existing in core and low permeability of core material, and the mechanical one that is enough larger ＂water wedging＂ action： （2） the mechanical mechanism of hydraulic fracturing can be explained with the theory and method of facture mechanics： （3） the boundary and stress conditions of laboratory, field or model tests should be similar to those in up-stream face of core of the dam, for instance, some fissures should be included in sample, and the water pressure should be forced from the surface of the sample; and （4） the numerical simulation to the development course of hydraulic fracturing is deformed and the effective way to study the hydraulic fracturing in core of earth-rockfill dam is to reveal the induced condition and mechanical mechanism, to develop reasonable criterion and to estimate and simulate by using numerical analyses.