Study On The Stability Of Jointed Rockmass Around The Newly Built Tunnel Under Complicated Urban Environment

With the rapid development and acceleration of urbanization, cities have beenexpanding. Metropolitan center area’s densely populated, and buildings are everywhere,crowded space, traffic congestion and other problems, seriously hampered the furtherdevelopment of economic and society. To meet the development of human society, toachieve sustainable development strategy, people gradually turn their gaze to thedevelopment and utilization of underground space. Due to the complex environment ofunderground rock and soil mass, rock mass is effected by the jointed cutting rockdiscontinuities, which have a negative impact on the stability of surrounding rock ofunderground caverns. Therefore, to study the stability of jointed rock during design andconstruction process is very important work.The Dongshuimeng Bridge&Qiansimen Bridge connecting tunnel located withinChongqing Yuzhong peninsula, which has characteristics of overlapping with theexisting rail line six, jointed rock developed, tunnel with large excavation. The paperbased on the real project, uses laboratory test, theoretical and numerical analysis tostudy the stability of new tunnel in the city with complex environment jointed rock.Work as follows:①It studies the strength character and deformation characters of rock underdifferent test conditions, by the test of uniaxial loading and conventional triaxial loadingthrough MTS815Servo-Controlled Rock Mechanics Testing Machine. Linearrelationship between peak strength and confining pressure, as well as shearing strengthparameters c、 φ, are obtained with the method of linear regression, based onMohr-Coulomb criterion.②The Hoek-Brown strength criterion is studied preliminary and the selectingmethod for parameters in the criterion is introduced particularly. Mechanical parametersof rock mass are estimated from rock mechanical parameters which has been got fromlaboratory.③The stability of jointed rockmass around the newly built multi-arch tunnel orneighborhood tunnel under complicated urban environment is researched with distinctelement software UDEC4.0. The characteristics of stress and displacement in tunnelsurrounding rock during excavation are studied to find out the large deformation regionand stress concentration region, so as to provide constructive opinions for design and construction of tunnel.④The stability of jointed rockmass around the newly built multi-arch tunnel orneighborhood tunnel under complicated urban environment is researched with finiteelement numerical simulation software MIDAS/GTS based on Hoek-Brown strengthcriterion, which verifies the reasonableness of constitutive relation.