Applicatiom Of Grouting Reinforcement Technology In A Subway Project In Qingdao

At present,urban underground rail transit has become one of the main means to solve urban congestion.However,in the underground urban space of subway construction,there are often a large number of underground pipelines and other soil layers which are not suitable for subway to cross directly.If the subway is built directly in this environment,it will easily cause collapse,water gushing and other engineering accidents,resulting in huge casualties and engineering losses.In order to ensure the stability of the working face and reduce the ground settlement and deformation caused by underground construction,manual reinforcement measures are usually adopted to ensure the smooth development of the project,and grouting reinforcement measures are more common reinforcement methods.Based on a subway project in Qingdao,the grouting technology is studied in this paper.The grouting technology is analyzed by means of theoretical analysis and field test.The following problems are mainly studied.(1)The background of the project is analyzed and studied,the buildings and pipelines around the construction area are statistically analyzed,and four hidden canals are emphatically analyzed.The regional geological environment and climatic conditions of the project are studied,and the two difficulties facing the project,groundwater influence and land subsidence,are analyzed.(2)Three kinds of grouting action principle are analyzed,and the factors affecting grouting effect are studied,which are grouting permeability,stability and water evolution.Focusing on the analysis of the performance requirements of grouting materials,through comparative analysis,the cement-sodium silicate slurry is finally selected as the grouting material for this project.(3)The curtain grouting technology used in this project is studied,and the curtain grouting is determined with 15 m as a cycle.The basic parameters of pre-grouting are determined according to the grouting material and the site conditions.(4)According to the actual situation of the project,P-Q-t curve method and borehole verification analysis method are adopted to check and evaluate the effect after grouting.The water seepage before and after grouting is measured.The data show that the water seepage after grouting is obviously reduced,indicating that the grouting has achieved the desired goal and effect.