The Lancang Galena Tuff Roadway Deformation And Instability Of Law And Supporting Programs To Improve The Study

Soft rock tunnel supporting is one of the greatest problems in mining security production. The problem of tuff tunnel supporting has always been disturbing LanCang Lead Mine's security production for many years. The tunnel in this mine has become very instability because the tuff here can easily get expansion and weathering, sometimes even get mudding when it is influented water. The serious results of this phenomena are roof fall, squeeze in two sides, floor heave and the broken of its full section. During them, the floor heave is the most serious one. In the process of governing this mine, the methods of concrete invert arch and wooden stand had been taken. But problems always occurred not long after that:the constant base enlarging, slope expansion and too many times of rework. All these had seriously affected the normal production of this mine and brought great economical loses.The 1700 level was taken as an example for all the researches done in this essay according to the details of this mine's broken situation.(1) Laboratory experiments of tuff. Many experiments were done firstly, like the micro-experiment, the water ratio experiment, the disintegration experiment, the swelling experiment, and the point load experiment, then I seriously analysised the tuff s deformation-failure law from its hydrological properties and mechanical properties. Finally I got several results:LangCang Mine's tuff contains manyclay minerals,most of which is kaolinite, and it also contains a certain rate of montmorillonite. The tuff here has very low substantial stebility, so it is a kind of medium dilatability soft rock. In the water and dry situation, it merely expand, disintegrate and weather;but when it is influented water, it's expansion ability would be greatly increased. It can expand in a very high speed and come up to a high weathering degree. In addition of the influence of the tempreture's dry-wet cycle and thermocycling, its broken process can be greatly accelerated. So from this experiment, I finally came to the conclusion that water is the main reason which brings the tunnel's broken, and formation pressure has also affected this in a kind of degree. So the clue of waterproof should be carried out firstly in tunnel protecting.(2) Relevant research about lime-stabilized soil.Throuth the experiment of lime's expansion in different lime ratio and water content according to the idea of lime improve tuff, I got the conclusion that it has a better improving result when its water content is 12%～15% and mix lime dosages is 15%. Then after anglicizing the rock samples by phase analysis, I got the reason for the enhance of the lime improved tuff s plastic limit, the depression of its penetrability and the improving of its intensity, which powerfully supported the idea of soil amelioration.Practical engineering had been taken as the research objects in this papper. The support method for the roof and the tunnel's sides is bolting and shotcrete wire, and the treatment scheme for the floor heave is soil amelioration. This treatment scheme has many advantages such as simple construction, reclamation convenience, can prolong the tunnel's using time and rapid rework. So it brings a magnificent economic benefit and social benefit for the enterprises. What's more, it provides a reference valued support method and research thought for the similar engineerings.