Experimental Study On The Saturated Soil Modified With New Technology Of Gas Drive Water Grouting

A variety of civil engineering,hydraulic engineering,mining engineering and other things that refer to massive foundation treatment,are often confronted with problem handling of the weak saturated soil body band.Grouting is an effective way to improve the weak rock mass,with the common method being cement grout and chemical grout.There are cupping grouting law seals up,the size difficultly to enter infiltrates,the water percolation rate difficultly low,mechanics intensity low,the modulus of deformation small and some other problems in the grouting method,the sleeve valve tube grouting method,drawing tube grouting method.For this kind of saturated soil reinforcement,technicians often use chemical grouting technology for processing at home and abroad.Influenced by differences in seepage start-up pressure,it is hard to lower permeability through Internet or occluded hole under conventional process,may form many grouting blind area,causing it difficult to achieve ideal grouting treatment effect as a whole.In the 1970s,Germans first used the compressed air law in tunnel processing to carry on draining water,openning up the gas drive water craft.By drawing from compressed air of the new Austrian tunnel construction method,the oil industry gas displacement technology,aquifer underground gas storage construction,aeration method and treatment of pollutants in soil and groundwater and emergency handling inflatable slope section water technology,they put forward the process gas drive water used in the chemical grouting engineering.Aiming at experimental exploration studies on basic theory and experimental simulation through new technology of chemical grouting in gas drive water,the main works and conclusions are as follows:(1)Based on the principle gas-liquid two-phase flow,the value of upper and lower limit of inflation pressure(the dominant controls parameter in the process of water drived by gas)is deduced,and is verified by doing experiment.(2)The test equipment is developed to study the new craft feasibility.The weak soil saturated with gas drive water chemical grouting test system,which is made up of the gas drive aqueous system,chemistry grouting system,the shell of tank system,and the monitor system,is developed to study the theory of gas drive water chemical grouting.The result shows that it is feasible to use gas drive water chemical grouting in the density of saturated soft clay layer,the higher the pressure is,the faster the water displacement is,so that weak soil saturated with gas drive water chemical grouting test system is reliable.(3)Simulation test of parameters under different working status was conducted,simulating the affection of different grouting parameters to grouting by using underwater epoxy hardener MS-1086 as typical materials.The results show that the higher the pressure,the faster the speed of micro-seepage grouting,but there exists upper limit of pressure;and when the pressure reaches its ceiling,serum will flow out directly along the passage,thus reducing the effect of grouting.(4)Grouting evaluation.Through the analysis to the grouting stone performance,including measures of the density measurement of core samples,analysis to structural surface,analysis to micro structure under microscopic,test to unconfined compressive strength and so on,acquired the physical property parameters such as the density of core samples,macro structure,micro structure and compressive strength,evaluate comprehensively and analyze the physical properties of core samples,and explore the feasibility of micro-seepage chemical grouting by gas driving water in saturated,compacted and deep-bed clay,analyze the reliability of grouting performance of indoor chemical grouting system and evaluate the test result of gas drive water seepage chemical grouting.The results show that the melts stone increase significantly,but the stone body exists partial hole flaw,which likely due to water driving is not completed.The residual water and air of stone body has certain affected the performance,and the specific impact degree needs further theoretical analysis and experimental verification.The application of gas driving water craft to the field of chemical grouting is a meaningful exploration,because this technology has relatively mature theoretical basis for it composite the tunnel compressed air method,oil production technology of gas driving oil,building of underground gas storage in the layer of water,treatment of soil and pollutants in underground water by aeration method and drainage method by side air inflation.The paper mainly studies the application of gas driving water grouting craft to the saturated soil layer,but still there are many theories in the field of chemical grouting remaining studied,including materials of chemical grouting,parameters of techno logy control,application object and so on,which need to be verified when applied in real project.