Research On The Properties Of Grouting Material And The Stability Of Reinforcement Structure Of Soft Surrounding Rock

Soft surrounding rock is easy to produce excessive deformation in tunnel construction.At the same time,soft surrounding rock often causes geological disaster such as roof collapse because the geological conditions are complex.Therefore,reasonable measures must be taken to control the excessive deformation of soft surrounding rock.As a basic method of stratum strengthening,grouting technology has strong applicability.However,when the geological conditions are poor,grouting technology alone cannot meet the engineering requirements,it should be combined with other reinforcement methods.In addition,different geological conditions have different requirements on the types and properties of grouting materials.Selecting appropriate grouting materials can ensure the quality of grouting and construction safety.Therefore,it is of certain significance to study grouting materials and relevant theories.In this paper,the composition of grouting material is optimized by orthogonal test and its basic properties are tested.A numerical analysis model is established to analyze and compare the deformation of soft surrounding rock before and after grouting.The specific research conclusions are as follows:(1)The factors influencing the performance of cement-sodium silicate slurry,such as water-cement ratio,content of sodium silicate and content of mineral powder,were studied experimentally,and some basic engineering properties of cement-sodium silicate slurry were tested.The water-cement ratio had the greatest influence on the gel time.When the water-cement ratio changes from 0.8 to 1.25,the slurry gel time and fluidity increased,the compressive strength first increased and then decreased,and the stone rate continued to decrease.(2)As an important factor to control the performance of cement-sodium silicate slurry,the content of sodium silicate can effectively improve the performance of cement slurry.The gel time and fluidity of the slurry increased When sodium silicate content exceeds 30%,but the stone rate and compressive strength decreased.(3)Mineral powder has higher activity.When mineral powder is added into cement-sodium silicate slurry,the gel time decreases first and then increases.However,increasing the content of mineral powder will increase the stone rate and compressive strength of the slurry.The addition of mineral powder will cause the hydration reaction to start earlier and generate a certain c-s-h gel,which improves the compressive strength.(4)Despite the grouting can improve the stability of soft surrounding rock,the grouting quality is influenced by many factors.Changing to material mechanics parameters of surrounding rock is limited,the increase of formation parameters after grouting reinforcement is reasonable range,the surrounding rock deformation decreases with the increase of angle of internal friction and cohesion.The formation parameters increases to a certain degree of tunnel vertical displacement deformation change rate decrease.(5)The settlement rate of the arch decreases after adopting the grouting reinforcement measures of the pipe shed.The settlement of arch roof without pre-reinforcement is affected by the distance of excavation section.The deformation of soft surrounding rock during tunnel construction is effectively controlled by the grouting reinforcement measures of pipe shed,and the stress of lining shotcrete decreases after the grouting measures of pipe shed are taken.