Study On The Tunnel Floor Heave Mechanism And Control Technology Of Nearly Horizontally Interbedded Surrounding Rock Tunnel With High Geostress

This paper aims at the deformation of the tunnel floor heave in the high gr ound stress area dominated by horizontal tectonic stress.The main research conte nt of the tunnel floor heave mechanism and control technology is through the us e of data research,theoretical analysis,numerical simulation,on-site monitoring.The influence of the influencing factors on the deformation of the tunnel floor h eave,the corresponding tunnel floor heave control technology is proposed,and th e feasibility of the control technology was verified by FLAC^3D numerical calculat ion software simulation,and the case analysis of the tunnel floor heave of Laoz houyan tunnel was analyzed.The main research contents are as follows:?1?Using the method of theoretical analysis and data investigation,The defo rmation characteristics of the tunnel floor heave of the layered rock tunnel are d ivided into:squeezing fluidity tunnel floor heave,deflection fold tunnel floor hea ve,shear dislocation tunnel floor heave.The main influencing factors of tunnel f loor heave deformation of interlayer rock mass tunnels in high geostress area do minated by horizontal tectonic stress are summarized:surrounding rock stress env ironment,surrounding rock occurrence,surrounding rock layer thickness and surr ounding rock strength.?2?In order to study the influencing factors of the tunnel floor heave of int erlayer rock mass tunnels dominated by horizontal tectonic stress,the above four influencing factors are selected,and the corresponding numerical calculation mo del is established by FLAC^3D to study the influencing rules of tunnel floor heav e under the action of single influencing factors and multiple influencing factors.The results show that under a single influencing factor,the area of the bottom o f the invert arch increases first and then decreases with the lateral pressure coeff icient,decreases with the increase of the dip angle of the rock layer,and increas es and then decreases with the increase of the thickness of the hard rock layer,Decreases with the increase of the elastic modulus of hard rock.Under the com bined action of multiple factors,the influence of various factors on the tunnel fl oor heave of the tunnel is ranked in order of lateral pressure coefficient>hard r ock elastic modulus>hard rock layer thickness>rock layer dip angle.Tunnel b urial depth and lateral pressure coefficient have the most significant impact on th e tunnel tunnel floor heave,followed by the surrounding rock strength,while the rock layer dip angle and rock layer thickness have little effect on the tunnel tu nnel floor heave..?3?In view of the high ground stress in the horizontal tectonic stress as the leading area of each layer of the floor heave of the tunnel rock mass deformati on characteristics,puts forward the deepening of inverted arch,applied pressure r elief hole for bolt and arrangement of three kinds of control measures,the nume rical simulation experiment results show that:deepen the inverted arch can reduc e the amount of the drum at the bottom of the tunnel,inverted arch 1.5 m to d eepen,the inverted arch tunnel floor heave quantity reduced from 12.72 mm to3.40 mm,reduced by 73.27%.The amount of invert floor heave can be reduced by reducing the bolt spacing and increasing the bolt length.When bolt spacing l=0.5m and length h=8m,the floor heave of invert decreases from 12.72mm to 6.17mm,a decrease of 51.42%.The deeper the pressure relief hole and the smalle r the spacing are,the smaller the tunnel bottom heave.When the pressure relief hole spacing l=1m and the depth h=4m,the invert floor heave decreased from12.72mm to 8.10mm,a decrease of 36.32%.?4?When the Laozhouyan tunnel in the high ground stress area appeared to be arched upward,the upper arch is used to deepen 0.5m,the second lining us es C40 concrete,the second arch of the upper arch is increased by 0.1m,and th e bottom of the tunnel is 8m long,four measures can play a better governance effect.The numerical control of various control measures is carried out separatel y,and the control effect played by deepening the arch is the most obvious.And through the on-site monitoring data after the rectification,the effectiveness of th e proposed control measures was verified.