Soft Rock Roadway Bolting And Support Mechanism Analysis And Engineering Applications

The technology of bolt-grouting support is a new kind of supporting technique in soft rock tunnels. The natural capacity of rock's mechanics is improved by grout and the effect of support for bolts is increased. It is embodied concretely: (1) With the adoption of grouting bolts, the cranny in wall rocks can be blocked up, the air can be isolated, the wall rocks can be prevented to be weatherized and make water, the strength of wall rocks can also be avoided to be lowered; (2) The lax broken wall rocks are commentated to a whole by liquid after they were grouted and the rock's strength is increased, so the wall rocks become a part of the support structure by using itself and become a whole with the original rock, and the roadway is made to keep stable but not easy to be broken; (3) The spray layer wall are filled with liquid after grouting, the stress is avoided to be concentrated because the load could be evenly acted on the spray layer and the support; (4) The pressure acted on the plank can be delivered to the two sidepieces and then to the bottom by reinforcing the sidepiece; At the same time, the concentration degree of loads acted on the motherboard can be weaken because of the enlargement of the combination arch's thickness, as result, the rock's stress is lowered and the heaving is alleviated; (5) The common bolt is made to be fixed the whole length after grouting, the layers are connected to a integral whole and bear the weight of loads, so the support structure's unity is increased.The theory of the bolt-grouting support is explained in this paper with it's present international condition, and on the basis of the analysis for the rule of soft-rock roadway's pressure the laboratory experiments are done for the purpose of designation; Secondly, the testing bolt-grouting roadway is simulated by computers and the interact ional mechanism and the distribution regulation of the stress's transformation among the bolt, liquid and wall rocks are analyzed; In the end, the application effect of the bolt-grouting support is examined by monitors analysis on site and the some improvable measures are put forward. This research result has an important meaning for improving the bolt-grouting support structure in soft rock roadways, enriching it's theory and designation and promoting the development of it's technology.