Development Of Modified Silica Sol Grouting Material And Its Sand Grouting Simulation

Grouting is a common means to improve the strength and impermeability of rock and soil mass.For different rock and soil mass,different grouting materials need to be selected.At present,although there are many varieties of grouting materials,each has its corresponding applicability and obvious advantages and disadvantages.Generally,the suspension grouting material has larger particle size and poor grouting performance;Solution grouting material has high price,to some extent,it has certain toxicity and side effects,the stone strength is not high,durability is poor.In view of the above problems,the silica sol is used as the main agent to develop a kind of sand grouting material with good grouting ability,durability,high strength and environmental protection.The main research contents and conclusions are as follows:(1)Preparation of modified silica sol green grouting material.Based on the previous research results,the properties of silica sol were discussed from the microlevel of molecular structure,and the mechanism of gelation and coupling agent modification was studied.On account of the key performance indexes such as gelling time,viscosity,impermeability or curing effect,chloride 2 was initially selected as gelling agent,acetic acid as pH regulator,intensifier 1 as reinforcing agent and coupling agent 2 as coupling agent,and then the optimum ratio of modified silica sol green grouting material is determined by orthogonal test.(2)Experimental study on the durability of modified silica sol green grouting materials.Based on long-term laboratory tests,the variation of strength,silica dissolution rate,volume change rate and permeability coefficient of modified silica sol-gel and its sand-consolidated body with time were studied under standard curing and water immersion conditions.The experimental results show that the green grouting material of modified silica sol has good durability.(3)Numerical simulation of sand grouting with modified silica sol green grouting material.Based on Lade-Duncan failure criterion,the generalized Bingham fluid constitutive model with time-varying slurry is used to simulate sand grouting with fluid-solid coupling theory,a two-dimensional numerical model of sand grouting is established.The grouting is performed by using different grouting materials,different grouting pressures and different porosity of sand.When the grouting pressure is 1.0 MPa and the mean initial porosity of sand is 0.4,the maximum deformation value of sand is 27.03 mm,and the grout diffusion radius can reach 1.47 m.(4)Application of modified silica sol green grouting material in engineering practice.Combined with engineering practice,the applicability of modified silica sol green grouting material in sand texture layer was studied.The results show that the anti-seepage and strength of the modified silica sol grouting material meet the engineering requirements,and it has high grouting ability and strong adaptability to sandy soil layers.It is a good green grouting material.