破碎岩体注浆加固体强度估计

Estimating strength of grouting reinforced bodies in broken rock mass

在注浆压力和时间满足规范要求时,注浆前岩体强度、注浆后加固体强度、浆液结石体强度是影响注浆加固效果的主要因素。在分析了已有纯水泥浆结石体强度试验的基础上,利用非线性拟合分析,提出了P.O.42.5水泥结石体28 d强度与水灰比之间关系的经验公式。对已有岩体注浆前后强度试验值进行了无量纲分析,建立了量纲为1的参量——强度增长率和原岩体与浆液结石强度比,进而通过非线性拟合分析,提出了破碎岩体注浆加固体强度增长率的经验公式。根据莫尔库仑强度理论,推导出岩体注浆前后剪切强度参数增长率的计算公式。在现场进行了破碎岩体注浆试验,结果表明,强度增长率试验值与经验公式计算值基本吻合,满足岩体工程注浆设计的需要。

When the grouting pressure and time meet the specification requirements, the main factors affecting grouting-reinforcement effect are the strengths of rock mass before and after grouting and of hardened cement paste. Based on the existing test data of pure hardened cement paste compression strength, to express the relation between the 28 d-strength and the water-cement ratio for P.O. 42.5 cement, an empirical formula is proposed by means of the nonlinear fitting method. Based on the existing test data of rock mass strength before and after grouting, using the non-dimensional analysis method, two dimensionless parameters are proposed： strength growth rate and strength ratio of original rock mass to hardened grouting, and then an empirical formula to describe the compression strength growth rate of the broken rock mass reinforced before and after grouting is proposed by use of the nonlinear fitting method. The equations for the shear strength parameters growth rate before and after grouting are derived according to the Mohr-Coulomb strength theory. Filed tests on grouting into broken rock mass are conducted. The results show that the compression strength growth rates obtained from the formulae are basically consistent with those obtained from experiments, and that they meet the needs of rock grouting design.