Research And Application On Composite Support Technology Of High Stress And Large Deformation Soft Rock Roadway

The support problem of soft rock roadway has always been an important and complicated technical issue in underground engineering.The geological conditions are increasingly complex.The high ground stress,high ground temperature,high osmotic pressure and strong disturbance affect the difficulty of support in soft rock roadway.The roadway has long been in the dilemma of“three highs and one low”:high cost of support,high difficulty of support,high degree of deformation of surrounding rock and low safety.Most roadways need multiple repairs,multiple expansions,and multiple supports,and it is hard to effectively control the deformation of surrounding rock and keep the stability of the roadway.In recent years,although the support technology and support theory of soft rock roadway have made substantial breakthroughs,there are still some shortcomings,which hinder the development of soft rock roadway support technology.At present,the existing high-stress soft rock roadway support technology can not meet the control of surrounding rock stability under different geological conditions,different stresses,different water environment and other conditions,and is still in the process of exploration and practice.Therefore,it is urgent to carry out research on the new foundation theory of soft rock roadway support to control high stress and large deformation soft rock roadway,and enable the mining activities to be safely and efficiently.This paper takes the 141712 transport uphill in Tucheng mine as the engineering background,refers to the related literatures at home and abroad,investigates the deformation and failure characteristics of high stress soft rock roadway,analyzes the deformation and failure mechanism of soft rock roadway,and proposed the"triple-shell"support theory,expounded the grouting support technology,and revealed the principle of“triple-shell”support.Use FLAC^3D numerical simulation to simulate different support schemes.Through different distribution characteristics such as stress,displacement and plastic zone,the optimal support scheme is selected.Finally,the support scheme is successfully applied and monitored through the site.The effect of the protection is good,and the following conclusions are drawn:1.Explained the definition,classification,mechanical properties and mechanical properties of soft rock study,the deformation and failure characteristics of soft rock roadway are systematically analyzed.The deformation and failure characteristics of the soft rock are mainly:internal squeezing,roof sinking,anchor cable anchor failure,metal mesh pocket The characteristics of tearing,serious bottom drum,serious section convergence,obvious muddy phenomenon and asymmetric deformation are analyzed.Based on this,the deformation and failure mechanism of soft rock roadway is analyzed,mainly from:surrounding rock lithology,geological conditions,supporting members,Analysis of water effects and other aspects.Finally,the system clarifies the principle of support for soft rock roadways.2.Proposed the concept of"triple-shell"support conception;the principle of grouting support technology was analyzed,and the analysis was carried out from three aspects:the network skeleton of the slurry,the narrowing range of grouting and the loosening circle,and the grouting to prevent water from strengthening the surrounding rock;the basis of grouting support technology Analyze the principle of action of the"triple-shell"support.The main principle is:it can avoid the weak link of support,improve the active bearing capacity of surrounding rock,maintain the integrity of surrounding rock of roadway,support mode is secondary support,support can moderate pressure,can prevent water erosion Function and so on.At the same time,the mechanical analysis model of the"triple-shell"support structure was established,and the calculation formula of the ultimate bearing capacity of the"triple-shell"was derived.Secondly,the calculation model of the"triple-shell"support structure was established,and the"triple-shell"elastic zone and plastic zone were derived,the formula for solving the stress and displacement of the fracture zone.3.Introduced the FLAC3D numerical simulation software,the principle of establishing the numerical model is expounded,and the 3D geological model is established based on the site investigation and geological data.At the same time,according to the field investigation and analysis,three kinds of support schemes were designed to simulate and compare the analysis.The results of numerical simulation analysis showed that:the anchor cable+grout+U-shaped steel support scheme is the best;at the same time,the selection of the support section can be based on Different geological conditions and service types of roadways are selected for different roadway cross-sectional shapes.For the roadway deformation and damage is serious,the cross-section size is large,the circular tunnel section and section requirements are not large,but the bottom drum is severely deformed,the horseshoe-shaped roadway section is selected,the roof is sunken,and the two gangs are more serious,but when the bottom drum is small Select the semicircular arch roadway section.4.Take the 141712 transport uphill in Guizhou Tucheng coal mine as the engineering background,according to the actual geological conditions,site investigation and theoretical analysis,it is determined that the support scheme of the roadway is the joint support scheme of the anchor?cable?+grouting+U-shaped steel,and the shape of the section of the roadway adopts a semicircular arch shape.Give the detailed introduction about monitoring purpose and monitoring principle of surrounding rock deformation in roadway,and the detection principle of the YJDM3.6mine laser roadway section detector.Field monitoring,recording and organize deformation and damage data of the roof,the two sides and the floor of the 141712 transport uphill roadway.The monitoring results show that after the completion of roadway support the surrounding rock deformation is mainly divided into three stages:sharp growth deformation stage,slow growth deformation stage and stabilization stage.The final deformation of the roof is 69.22mm,floor heave amount is 64.11mm,two sides approaching amount is 72.45mm.The grouting support technology improves the active bearing capacity of the surrounding rock itself and effectively controls the instability deformation of the surrounding rock of the roadway.