Research And Application Of Cement-based Anti-dispersive Swelling Grouting Material

China’s underground engineering construction is in a booming stage.During the construction process,geological disasters such as water inrush and stratum collapse are frequently encountered,which seriously threaten the safety of people’s lives and property.Especially in the karst area with poor geological development and vast area,the water inrush disaster presents the characteristics of large flow and high velocity,which causes a large disaster area and a wide range of influence.Therefore,how to effectively block the water inrush disaster has become a key problem in engineering construction.In order to solve the problems above,this paper develops a Cement-based Instant Sealing Material(CIS material)based on core-shell structure control by means of indoor test,theoretical analysis,model test and engineering application.Through the"promotion-retardation" mechanism of hydration process,the self-stabilization ability of cement-based materials in dynamic water environment is greatly improved;The physical and chemical expansion control technology is used to realize the expansion control of cement-based materials slurry,and the synergistic relationship between expansion characteristics and anti-dispersion characteristics of cement-based materials is expounded.Combined with physical model test and indoor anti-erosion test,the application research of dynamic water plugging of cement-based anti-dispersion expansive grouting material is carried out,and the grouting design parameters and control methods considering dynamic water velocity,structural width and anti-erosion are put forward,which have been successfully applied in the water inrush control project of China Resources Cement Hepu limestone mine.The main research work and achievements are as follows:(1)Based on the study of the induction period of cement hydration,the design concept of"accelerating the hydration process of cement+improving the self-stabilization ability of cement particles" was put forward.Through the control method of "accelerating the hydration process of shrinkage+physically coating hydration particles+chemically complexing hydration ions",the remarkable anti-dispersion ability of cement slurry in moving water environment was realized,and a cement-based anti-dispersion grouting material was developed.The material has the characteristics of adjustable initial and final setting time(the adjustable range of initial setting time is about[13 s,65 s],and the adjustable range of final setting time is about[30 min,255 min]]and high running water retention rate.In the running water environment,(the flow rate is 1.2 m/s),the retention rate of materials is over 80%,and the retention rate of the slurry with the best ratio is as high as 92.3%.(2)Based on the stability of the expanded slurry,the synergistic relationship between physical and chemical expansion control technology and cement-based anti-dispersion grouting material is explored.Through macroscopic and microscopic tests,the mechanism between the type and content of expansive agent and the anti-dispersion of cement-based materials is clarified.The compatibility of different physical and chemical expansion methods with cement-based anti-dispersion grouting materials is determined,The chemical expansion method achieved 3.28%-4.8%volume expansion within 20 minutes,and the physical expansion method achieved 16.48%-32.27%volume expansion,which provides certain theoretical basis and guidance for the engineering applicability of materials.(3)Through the indoor test model,the effects of slurry parameters,characteristics of water inrush and grouting technology on slurry diffusion form and plugging efficiency in the process of plugging water inrush are studied,and the quantitative relationship between plugging time,slurry consumption,grouting pressure,slurry retention rate and water inrush conditions such as flowing water velocity and structural size is established respectively,When the water-cement ratio increased from 0.7 to 1.0 and 1.2,the gushing sealing time increased by 125%and 162.5%,the hydrodynamic flow rate increased from 0.5 m/s to 0.9 m/s and 1.2 m/s,the maximum decrease of slurry retention height was 27.78%and 45.45%,furthermore the grouting design and control methods for pipeline water inrush plugging are put forward.(4)The anti-erosion characteristics of CIS material under service conditions are studied.The anti-erosion performance of CIS material is systematically studied from macro and micro scales,and the change law of mechanical properties and pore structure of stone body under the action of different types and concentrations of corrosive ions is clarified,revealing the micro-mechanism of anti-ion erosion of CIS material.(5)Based on the water inrush control project of Yantian limestone mine of China Resources Cement(Hepu)Co.,Ltd.,the field test research of CIS materials independently developed was carried out.Based on the characteristics of water inrush disaster in Hepu mine,the design method of plugging parameters of karst dynamic water grouting in coastal area is put forward,which successfully plugs the water inrush point of Y02-15 in China Resources(Hepu)cement limestone mine,with a total water reduction of 22,725 m3/d,and the control effect is stable and reliable,with remarkable economic and social benefits.