Research On The Key Techniques For Construction Of Collapse Section In Uneven Weathered Granite Tunnel

In the tunnel construction,when the surrounding rock mass of tunnel tunnel passes through is more homogeneous,the excavation and support of the tunnel are relatively simple,or adopt mechanized excavation or excavation by drilling and blasting method.Support measures Easier to implement.However,for complex geological conditions of the strata,such as in the excavation section and in the extension direction of the excavation,there are often two or more different strata that make up the environment of the tunnel,and two or more stratigraphic works When the geological difference is very large,a kind of V-to VI-grade wall rock with extremely low strength and poor self-stability,while the other kind of wall rock can reach Class III or even III with high strength.Excavation should adopt Drilling and blasting excavation,and between the two strata is often the passage of groundwater,the intensity of a layer of rock is very negative.For such soft and hard surrounding rock tunnel,if builders lack of understanding,not enough attention in the construction process is often due to improper handling of different levels of cave deformation is difficult to converge,the settlement of the roof is too large,or even infringement And landslides and other different engineering accidents eventually led to more serious delays and costs of construction projects such as the phenomenon of such phenomena as the Liuyang River Tunnel in Changsha-Wuhan high-speed railway,the Mizuai section of Guangzhou-Foshan section and the Shigougang Tunnel on Heng-Kun Expressway.Therefore,this article has carried on the research on the key technology of the construction of the soft under the hard granite tunnel collapse treatment.As a Master of Engineering thesis,this thesis mainly combines the theories of engineering geology,geotechnical mechanics and blasting vibration theory,semi-empirical semi-theory and numerical analysis simulation technology to discover and summarize the mechanical behavior of rock and soil body and structure in practice And response rules.Through comparative analysis of theory and practice,repeated practice verification,summarized and concluded a set of safe and reliable key technology and method of tunnel construction on soft and hard undergrowth.In this paper,Shantou to Zhanjiang Expressway Jiexi Daxi to Boluo Dam section of a two-way six-lane expressway tunnel project as the project,the soft under the hard granite tunnel collapse treatment of key technologies for the construction of the project,mainly from the following aspects the study:(1)The paper analyzes the difficulties in the tunnel construction of Shangshangxia hard granite.The basic situation of the tunnel and the condition before and after the landslide are introduced firstly.Then the physical characteristics of the Shangshangxia Hard Granite are analyzed from the engineering geological conditions of this tunnel.The deformation mechanism of the weathered granite is analyzed from the aspect of geotechnical mechanics.The reason for the tunnel collapse;provide the basis for the following research.(2)Study on roof collapse treatment and arch replacement construction technology in hard rock tunnel of soft built area.First,using Midas / GTS commercial geotechnical numerical simulation software,the model was established by numerical simulation technology,and the stress and deformation characteristics of rock mass,soil mass and lining structure during the construction of Shanghaoxiaowei granite tunnel were calculated and analyzed.Based on the numerical simulation analysis,proposed and implemented the technical measures of landslide treatment and arch replacement construction;at the same time,through the deformation and force monitoring of the tunnel body structure,real-time feedback on the soft surrounding rock and The mechanical behavior of the lining can provide a dynamic basis for the implementation and adjustment of the technology.The results verify that the analysis of the mechanical response of the upper and lower soft surrounding rock and structure during construction is reasonable.The treatment technique in this paper is safe and reliable.(3)Mainly studied the construction technology of tunneling controlled blasting in Shangshangxia hard surrounding rock tunnel.After dealing with the weak part of the surrounding rock,the need to excavate the hard part of the surrounding rock,which involves blasting vibration research.In this paper,the traditional blasting semi-empirical theory is used to determine the relevant blasting parameters.In the Midas / GTS dynamic analysis model,the rock mass in the hard part is simulated and the structure induced by controlled blasting Dynamic response law and safety.Finally,through the on-site blasting vibration monitoring,it is verified that the construction technology of controlled blasting of soft and hard surrounding rock tunnel is reasonable and feasible.