The Surrounding Rock Stress-Strain Of Laoling Tunnel Along Chaoyang Town To Changbai Highway

With the rapid development of our national economy, the scale ofhighway construction has been expanding day by day, and the properties offast, comfort and beauty have been requested. Therefore, the development ofhighway tunnel construction has been driven and promoted. Tunnel project isexcavated in rock mass, while rock mass, which is one of the mostcomplicated and incomprehensible materials in technological discipline, ispart of geological body that undergo deformation and destruction, thereforethe mechanic state of underground structural is extremely complicated, it hasthe property of trinity of structure, material and load. The traditional"structure - load "model has already been no longer suitable, it needsdescription by solid mechanics model border terms and variety of mechanicparameters. The stratum-structure method, which regards the structure andthe stratum as a whole to perform stability analyses, has receivedconsiderable development in structure design in underground engineeringsince 1970s. Variety of calculation models have been set up according to theconstitutive relationship between surrounding rock and structure materials.Some related programs have been worked out, which promoted thedevelopment of calculation theory in underground engineering. Butsurrounding rock – support systematic mechanics mechanism is not veryclear up to now, the piecemeal change of initial ground stress field and rockmechanic parameters as well as the imperfect research of rocky materialfailure criterion and the variety of failure forms indicate the more seriouscomplexity of tunnel project than ground project. This paper analysis the stress-strain of surrounding rock by numericalsimulation method. According to stress concentration coefficient to divide thetunnel surrounding rock. At the same time, calculate the axial force of theanchor bar. Revised design is implemented in linear structure according to thepartition of stress concentration and the axial force is consideration whencome to the anchor bolt length. At last, using the theory of bearing arch toverify the safety of the new designing support system. The conclusion isreasonable. The analysis processes are as fellows: 1.According to the regional geological and engineering geologicalconditions of Laoling tunnel along Chaoyang Town to Changbai Class IIhighway, the actual surrounding rock classification, with combination ofconstruction method, has been performed using acoustic wave test, point loadexperiment, as well as rebound test and some other geological methods (suchas sketch and extend chart), after comparison with that of survey and designstage which has disadvantages in exploration methods, tools and apparatus,as well as the complexity of underground rocks, certain difference is硕士毕业论文 60朝阳镇至长白公路老岭隧道围岩应力应变分析confirmed , which indicates that implement according to original design willcertainly cause economical waste and latent failure in safety 2. Stress-strain analyses of the tunnel surrounding rock has beenconducted using FEM according to the real rock classification and surveymaterial-provided physical and mechanical parameters to confirm thedistribution of surrounding rock stress, plasticity district and displacement.Meanwhile, comparison has been carried out between non-liner andafter-secondary support on stress and strain distribution 3. The concept of " stress concentration coefficient " has been induced,which is defined as the ration of maximum stress (or peak stress) σm toreference value σ0 (which should be vary in different conditions). In thispaper, σm and σ0 are correspondent to the maximum or minimumprincipal stress of each element, respectively. Since they not only reflect thedegree that the stress concentrates, but embody the safe condition of eachunit at the same time because they are the two important parameters in M-Cfa...