Study On The Preparation Of New Grouting Material For Regenerated Roof

China is rich in coal resource, that the life-style of giving priority to coal energysupply pattern is difficult to be changed as a developing nation. Rock stratum of goafcollapse has great effect on ground subsidence, underground mining engineering and safetyextraction of coal layer. As the important foundation of goaf safety mining, regeneratedroof has an immediate impact on production efficiency of coal mine. And being the keypart of regenerated roof, grouting material is able to promote the forming time and increaseload capacity. Simultaneously it prevents the goaf spontaneous combustion to guaranteeingthe safety of goaf. Thus grouting material is an important factor in safety mining for coalmining face.This paper was based on the study of the deficiency of grouting materials used inother Gob， and take into account the high loading capacity and strong stability offoundation and road surface prepared with limestone soil，using pure clay grouting andother additives such as lime and cement，study the effects of multiple composite system onthe stability and mechanical properties of grouting material, produce a new groutingmaterial with a high consolidation strength and excellent stability. IR and XRD patternswere using to analyze the relationship between composition, structure and performance ofnew grouting materials. The influence of Gob environment on new grouting materialproperties was analyzed, and ANSYS finite element simulation were using to study theeffect of different mining depth and results before and after the injection of groutingmaterial on rock stratum displacement and rock stratum variation subjected to force. Themain results are as follows:(1) The cement and lime have a great influence of drainage rate and sedimentation ratefor clay grouting material but they have less impact for concretion rate and viscosity.Adding the cement and lime, the drainage rate of grouts and the compressive strength willbe increased; the concretion rate of grouts will be shortened. Water-solid ratio has a greatinfluence of stability for grouting material. Increasing the water-solid ratio the drainage rateand sedimentation rate of grouts will be improved, the concretion rate and viscosity will bedecreased.(2) The compressive strength of clay-cement-lime grouts reaches to the peak when thelime dosage is6%, the cement dosage is12%and sodium silicate-calcium chloride dosageis0.5%. The optimum mass ratio is: clay: cement: lime: sodium silicate:calcium chloride (3)=100:12:6:0.25:0.25and the stability is well. Simultaneously, the consolidation ofnew grouting material can be made up of pressure consolidation and chemical reactionconsolidation in the condition of pressure.(4) Rock stratum of goaf collapse take on a distribution of "saddle shape" withANSYS finite element simulation. Adding the mining depth, the maximum terranedisplacement, the maximum horizontal stress and the maximum vertical compressive stresswill be increased, the maximum vertical tensile stress will be decreased. Effectiveness ofgrouting is conspicuousness and decrease subsidence is45.7%by using new groutingmaterial.