| Rock mass is a naturally occurring geological medium with various structural forms and complex occurrence conditions.Various excavation activities and underground engineering carried out in rock mass are inevitably affected by the geological environment in which it is located.Groundwater is a must in underground engineering.One of the key problems to be solved is that the existence of various water sources and infiltration channels,triggered by special conditions,will cause large-scale water damage accidents,flooding wells and hurting people,damaging equipment,and overwatering of surrounding rocks has extremely adverse effects on the stability of the tunnel.Therefore,it is of great engineering significance to study the surrounding rock stability of the waterway.This research focuses on indoor test research,and at the same time,it is verified and expanded by combining numerical simulation.Stability research has certain guiding significance and theoretical value.The main research contents,methods,results and conclusions are as follows:（1）Based on the orthogonal experimental design scheme,the L16（4~3）fluid-structure coupling similar material physical and mechanical properties and hydraulic properties tests were carried out,and the compressive strength,elastic modulus,and water absorption of similar materials under different combinations were obtained.The experimental data of,softening coefficient,permeability coefficient,tensile strength and density reveal the influence of factors such as quartz sand content,cement:gypsum and organosilicon concentration on the mechanical properties of materials,and obtain the multivariate analysis of fluid-solid coupling similar materials.The linear regression equation;combined with the model frame size,the three similarity theorems and the Matlab overdetermined equations,the ratio of similar materials in the test was determined as:quartz sand=81.32%,cement:gypsum=1.38:1,organosilicon concentration=31.6%.（2）Model tests are carried out for the stability of surrounding rock of overwater roadway,the L9（3~3）orthogonal test of three influencing factors of tunnel burial depth,water-passing height and water-passing time was designed,and the variation law of stress and displacement of roadway excavation,and the variation law of stress and displacement of each factor during and after roadway drainage was studied.It is concluded that the influence of the water passage height of the tunnel on the stability of the surrounding rock of the tunnel is greater than that of the water passage time and the influence of the buried depth on the stability of the surrounding rock of the tunnel.（3）Using Midas GTS NX numerical simulation software,the three-dimensional numerical calculation model of tunnel excavation and the two-dimensional numerical calculation model of water-passing tunnel are established,and the change law of stress and displacement with the excavation step in the process of tunnel excavation is analyzed.And the stability of the surrounding rock of the tunnel during and after the tunnel has passed the water for a certain period of time.It is concluded that the influence of the water-passing height on the stability of the surrounding rock of the tunnel during the passage of water>burial depth>the influence of the water-passing time on the stability of the surrounding rock of the tunnel;within a certain period of time after the passage of water,the water-passing height affects the stability of the surrounding rock of the tunnel.The influence of property>water passage time>the influence of burial depth on the stability of the surrounding rock of the tunnel. |
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