Study On Curtain Grouting Technology In Rich Water Area Under Complicated Geological Conditions

With the construction and development of the transportation network,the proportion of the tunnel project is more and more larger,the construction of highway through the tunnel with water rich often appear.In the previous survey and design of railway and highway tunnel,due to the limitation of various factors,the tunnel had to cross from the rich water area;at the same time,there will be a lot of water in the construction process,such as groundwater,underground river,it also brings serious difficulties for the stability of tunnel surrounding rock.At present,the construction experience of the tunnel through the rich water area is mainly from the railway tunnel,In the field of highway tunnel construction examples appear less.Therefore,how to ensure the safe passage of the highway tunnel containing high water area measures strata and rich water area,the study of the stability of surrounding rock is great significance.The study is based on the tunnel section of Sanquan highway Nanchuan to Guizhou of Chongqing,we establishment of the theoretical system model,laboratory experiments,numerical simulation,combined with the field test data,and actively carry out the tunnel through the water rich areas of the study of the key technology,and put forward advanced deep hole curtain grouting technology,research on tunnel water treatment,so as to ensure the safety of the tunnel through rich the water area,improve the precious experience for the corresponding water rich area tunnel,the main conclusions are as follows:(1)Whrough the study of groundwater in fractured medium seepage,seepage characteristics of groundwater under different conditions and studied the mechanism of seepage field and stress field interaction,obtained the formula between stress field and seepage field should be.The stress field is affected by the thickness of the fissure structural plane,thus changing the permeability of rock;seepage field and stress field by changing the environment,thus affecting the stress field,the interaction between the two is in a dynamic balance.(2)We use the field hollow body to lift the method to test and laboratory Kaiser effect in-situ stress test of K4+925.00~K7+577.632 segment of right tunnel,Comparative analysis of test results,obtained the initial geostress,the maximum principal stress ratio is 1.22,the intermediate principal stress ratio is 0.83,the minimum principal stress ratio is 0.90,and the principal stress direction and angle of approach.(3)Through the study of groundwater in fractured medium seepage,seepage characteristics of groundwater under different conditions and studied the mechanism of seepage field and stress field interaction,obtained the formula between stress field and seepage field should be.The stress field is affected by the thickness of the fissure structural plane,thus changing the permeability of rock;seepage field and stress field by changing the environment,thus affecting the stress field,the interaction between the two is in a dynamic balance.(4)Because of the increase and extension of the distance between the crack of the rock mass,the underground water will affect the stress field and the change of the strength of the rock mass.Therefore,3 typical sections are selected,the cross section is 80 m,and the surrounding rock grade is grade IV,and the field stress and displacement test are carried out.The three sections are respectively embedded vibrating wire pressure gauge,and are respectively arranged on the level of a convergence monitoring point,three vault monitoring points,were used to analyze the influence of the geological radar research groundwater seepage loose zone of surrounding rock of the tunnel,the tunnel surrounding rock loose circle.A range of tunnel surrounding rock loose zone measuring multi-point displacement meter,verifies the results of surrounding rock loose zone of tunnel geological radar measurement is accurate.(5)The K6+400~K6+850 section(not)of Sanquan tunnel considering multi field coupling conditions of the effect of step construction on stability,Analysis of the distribution law of seepage field,stress field,displacement field and plastic zone in the process of tunnel construction and curtain grouting.To study the influence of seepage field on the physical field of karst water rich region,and the results of the study are compared with the results of the above experiments,which are complementary to each other to ensure the reliability of the research content.Simulation study on curtain grouting in tunnel K6+400~K6+850 Sanquan,selection of grouting circle thickness is 2m,4m,6m and 8m,and combined with theoretical formula and empirical formula,the safety thickness of grouting curtain,we finalize the tunnel Sanquan curtain grouting circle thickness is 8m.(6)We research on the construction technology of curtain grouting in the tunnel site,and the horizontal and the roof displacement of the tunnel are compared and analyzed after the curtain grouting.the grouting material with cement-water glass slurry was put forward,according to the theoretical calculation and numerical simulation of the proposed scheme is suitable for Sanquan tunnel deep hole curtain grouting and procedures,given the relevant construction parameters,with guidance and reference value for the design and construction of geotechnical engineering grouting scheme;curtain grouting by monitoring the amount of test results of tunnel roof subsidence and horizontal convergence measurement method.Draw the curtain grouting has an equally important role of water plugging and the tunnel surrounding rock stability.