The Test Study On Grouting Reinforcement Soil And Engineering Application

Grouting technology as one of the key technology in various kinds of foundation treatment and reinforcement of rock and soil,has been widely used in practical engineering.With the progress of science and technology,people's consciousness of time and cost concept is gradually enhanced,the requirements of grouting technology is more sophisticated and demanding.Therefore,how to deal with the problems of reinforcement under various geological conditions and the expansion of slurry and predict the effect of grouting on the grouting process become urgent issues.Based on the above issues,the paper is supported by the building science and technology key project “Super large thickness characteristic loess structure and basic optimization research”(Grant No.JK2014-34).The gel properties,erosion resistance and micro characteristics of composite cementitious fast-gelling grouting material were studied from macroscopic to microcosmic;the expansion of grouting and its effect on soil under different conditions were studied by grouting model test;the filling rules and grouting effect of grout in soil were studied by field grouting test.The main contents and achievements of this paper were as follows:(1)The study on gelation properties of composite cementitious fast-gelling grouting material was carried out by orthogonal test design and relying on the test index to find the influence factors.The study found that the main factors affecting the gel-time of fast-gelling grouting material was retarder(Na2HPO4),and the main factors affecting the compressive strength of the material are: water cement ratio,sodium silicate,water reducing agent,retarder(Na2HPO4).(2)In this paper,the erosion resistance of the composite cementitious fast-gelling grouting material was studied.Research shows that the reason of the strength reduction of grouting material in the environment containing SO42-and CO32-was caused by the expansion and tension of Ca SO4 and Ca CO3.(3)The grouting model test under various conditions is designed,and research shows that when using different different water cement ratio,we can find that the water cement ratio increases,while splitting time was shorter,and the water cement ratio was small,the slurry viscosity,the formation of hydraulic fracturing was slower.Because of the short gel time,the composite cementitious fast-gelling slurry had a small splitting radius.After entering the soil,the viscosity of the slurry increases sharply,the flow rate became smaller,and the cracks can't be expanded.(4)Based on the practical project,the grouting test was carried out.The study suggest that if the grouting pressure can be released,the splitting and compaction effect was better when take different grouting methods.On the contrary,When thegrouting pressure can't be released,the splitting and compaction effect was small.The grout vein and cement pile formed by slurry can not only fill the fissures of the soil,but also act as a framework for the whole soil.And when applying composite cementitious fast-gelling grouting material to the reinforcement of the water rich area,we can find that it has a broad prospect of engineering application.