| In order to adapt to the rapid development of the national economy, The western region of the pace of road construction is accelerating,Some deeply buried tunnel works have started. Geological environment conditions is complexity in depth of the earth to construction project, often faced with the threat of the hign geothermal, high geostress, give the project a seriously impact on the building. At present, hign geothermal, high geostress bring about with the depth increase, has become a pressing problem.The research of this paper is hign geothermal, high geostress Gaoligong mountain tunnel, which is in the west of YunNan. On the basis of depth study of the region geological background conditions, typical of this area work at distribution of geological disasters, disaster-causing mechanism has been reviewed. Analysis of the tunnel surrounding rock and the lining parameters, especially thermodynamic parameters, on numerical simulation of tunnel excavation, at the same time analysis of temperature field change and temperature stress changes; study of the construction measures and support forms under the high grothermal conditions, In order to select a reasonable auxiliary cooling measures and the best support forms; Application of analytical method analysis the stress field in the project area, find out secondary stress distribution discipline after the tunnel excavation; Reference already existence the research data about rockburst or large deformation, summary the occurrence of mechanism and monitoring and forecasting about rockburst or large deformation, the use of finite element analysis of the mechanical behavior of the tunnel, at the basis of mechanical analysis, bring out reasonable support the principles and engineering measures of rockburst or large deformation under the high grostress condition. Adopted by the above research, the major conclusions are as follows:(1)After tunnel excavation ventilation 20 hours, tunnel wall temperature down to thirty point thirty five degrees, rock arch foot has maximum temperature stress; The primary support temperature stress at the foot arch is largest, the minimum temperature stress at wall; The secondary lining temperature stress at the foot arch is largest, the minimum temperature stress at Vault;(2)Temperature stress is negative load in rock wall after the tunnel excavation, easily lead to tunnel spalling, cracking, etc, so after excavation express shotcret and rock bolt support, are beneficial to both stability of surrounding rock and tunnel cooling.(3)Under the high geostress condition, analysis of the tunnel to draw a different coefficient of lateral pressure dome and the sidewall of the radial and tangential stress changes principle; Numerical simulation analysis of tunnel surrounding rock and support of the loading characteristics, make a qualitative prediction about rockburst and large deformation, to be taken corresponding engineering measures... |
