A Model Tester For Grouting Simulation Under High Pressure In Rock Fissure And Model Exper-imental Research On Plastic And Early-strength Grout By Grouting Simulation

The grouting quality become more and more difficult to be controlled as the depth of pregrouting is increasing, and the engineering geological condition become more and more complicated, especially in the rock stratum with wide fissures in deep shaft.This paper based on imbursement of the "11th Five Years Key Programs for Science and Technology Development of China"(NO. 2008BAB33B02) and National Engineering Laboratory Research on Coal Mine Shaft Construction Technologies, successfully developped a model tester for grouting simulation in rock fissure,which can work safely under high pressure. Firstly, based on the analysis of the grout flowing in rock fissure, a single fissure model of parallel plates was established; in order to meet study of grouting simulation in rock fissures of deep stratum, a fissure model which can work safely under high-pressure was successfully developed; an automatic monitoring system for grouting was set up, and some test data such as grouting pressure could be record automatically. The new tester have a lot of advantages as following:(1) It has the characteristics of bearing high pressure and sealing tightly, whose maximum working pressure is 36MPa. It can simulate the grouting in rock fissure with in 850m～1200m depth.(2) It is adjustable about the length and width of the fissure model;(3) Considered about the influence of underground water, it could detect the dispersal distance and filling of the fissure.In order to accelerate the application of the plastic and early-strength grout, making use of new model tester, the author completed some research work on grouting simulation in rock fissures under high water pressure for the grout. By the results of simulating experiment, some grouting laws in rock fissure under high water pressure have been discovered as following aspects:(1) There are three kinds of change curves of the rule of grouting pressure P with the grouting time t: gently, gently-ascending-decline- gently-ascending, and gently-ascending.(2) The grouting effect of the former kind P-t curve is not perfect, and the grouting quality of the latter two kinds of the P-t curves are very good, which could resist against the high underground water pressure in 1200m depth stratums;Based on the study of grouting simulation, it was proved that the plastic and early-strength grout is one kind of good grout with many advantages, especially for rock mass fissures grouting engineering in deep shaft.