The Research For The State Grouting Experiment In Cracked Rock Mass

Many methods in current geotechnical engineering field are practiced for strengthening rock mass such as the technology of anchors, pre-stressed anchoring cable and so on. Grouting has also been proved of a useful way to strengthen rock mass which uses cement or other materials to fill up the fractures and voids in rock mass. As a result of this, the stability is improved ,the permeability from the groundwater is reduced and the rock mass's ability of resistance to force damage is increased as well. But some problems spring out with it's wide application : the theory for grouting is immature and it can't keep up with the pace of it's application ; else, the construction of grouting is complicated and improper management operates or random construction has led to higher price than other reinforcement methods.The research for this paper is based on a joint-rocked slope by the Chang-Zhang (ChangDe and ZhangJiaJie, west cities in HuNan, central-south China) expressway in construction .The slope is strengthened by using cement-grouting technology. Ahead of the grouting design and large-scale construction, an in situ grouting experiment is necessary to master reasonable grouting parameters for the design or construction such as the grouting pressure and injection quality ,it's spread of cement mortar in the cracks of the rock mass and so on.Around the experiment, an investigation about the in situ engineering geology and hydrogeology is carried out and the parameters which reflect the rock or rock mass' mechanical performance is also acquired according to some state rock's experiment results .On the basis of these work ,an evaluation is given for the engineering geology and hydrogeology's influence on grouting and some parameters for the grouting experiment is firstly acquired by theoretically probing or practicing other means according to the result of in situ engineering geology investigation.The method of in situ grouting test is called all stage ,orifice-closed and non-circulation grouting which has the prominent advantage of simple operation and fast construction. According to the data statistics which is got at the process of stategrouting experiment, some relations between the grouting parameters under different stratum situations are got .A relation curve is drawn for the cement slurry injection quantity variety by offering different pressures. By utilizing this relation curve, an experience formula is summarized; else, the variable relation between the time and injection rate under the same grouting pressure is founded.Finally, the result of the state grouting test are analyzed Including thereinforcement effect for grouting cement mortar and some suggestions about the grouting parameters and materials are drawn out for the design and construction in the paper.