Research On The Influence Of Radial Grouting On The Secondary Lining Of Water-rich And Weak Surrounding Rock Tunnel

In water-rich and weak surrounding rock tunnel excavation will often encounter have contact with the surface water of soft fractured,when construction during the dry season,the area of groundwater is very small even without obvious groundwater to tunnel secondary lining after the completion of the storm season,the underground water will be sharply increased,the underground water will suddenly increase.If at this time lining unobstructed drainage system,it will cause excessive discharge of groundwater,thereby causing damage to the environment;if this lining drainage system blocked,it will cause behind the lining water pressure is too large,resulting in secondary lining cracking,seepage disease.Practice has proved that in this case the reconstruction after removal of the secondary lining or thickened there are many adverse effects,and the piecewise radial grouting method not only can avoid security risks after removal of the secondary lining and avoid the direct thickened secondary lining can not meet the construction clearance requirements.However,there is little understanding of the action mechanism of the segmental radial grouting on the secondary lining.Based on the analysis of the grouting theory in rock mass,set up a piecewise radial grouting numerical model using the finite element method,grouting process in the effect of secondary lining the main factors were studied,obtained a series of meaningful results:(1)Analysis and contrast the effect of different grouting order of secondary lining,proposed the safety of grouting sequence,of grouting construction sequence selection has guiding significance;(2)Analysis the influence of different classes of surrounding rock near the lining grouting section that initial period of grouting pressure on the secondary lining,puts forward the reasonable range of different surrounding rock in the initial period of grouting pressure,grouting pressure parameters of the initial segment with the selection of guiding role.(3)Analysis the influence from the lining was much higher than that in the second and third paragraphs in different grouting pressure in radial drilling of secondary lining,grouting pressure in each segment selection and combination pressure optimization is of great significance.(4)The finite element model is established based on the radial grouting engineering of Shuangbei tunnel,the results of this study and engineering actual grouting comparison,analysis of the piecewise grouting process in every segment of the grouting pressure value rationality,and put forward the optimization of radial grouting scheme.