| China has a vast territory, and has a large difference climate between north region and south region, and has a typical Alpine dry climate, high temperature and humidity climate zone, such as Guangdong, Hunan, Guangxi, Fujian and other places, the annual accumulated temperature is high, humidity is high.These regions have nearly 50% of the railway, highway tunnel, tunnel portal section of the tunnel under the high temperature and humidity environment for a long-term, the accelerated deterioration of surrounding rock and lining, easy to form a chronic diseaseAiming at the problem, this paper carried out the thermal and humidity mechanical theory of rock, and carried out the thermal and humidity stress and the formula deduced. And to carry out the high temperature and high humidity caused by crack propagation analysis, assignedfield numerical analysis combined with the example of Guangzhou-Shenzhen-Xiangganghigh speed railway tunnel. The author has been done a lot of work and come to a conclusion, the main contents are as follows:1.Study on the change of the climate’s temperature field and humidity field is studied. According to the heat conduction equation, using the finite difference method, it is concluded the distribution equation of the surrounding rock in the three dimensional temperature field.2.Derivation ofelastic constitutive equation of rock analyzed by clastic mechanics method considering the effect of temperature thermal, combining with the concept of stress intensity factor of fracture mechanics, the calculation of the crack tip stress field and displacement field. Considering the random distribution of rock mass fracture, on the basis of the coordinate transformation to calculate the arbitrary direction of the crack tip stress field and displacement field, obtained the main stress of crack tip, because calculation based on fracture mechanics; Finally using Matlab software programming to calculate the concrete example.3. Combined the interaction of temperature field and humidity field common role, according to the principle of humidity diffusion, considering the effects of temperature humidity, obtained the humidity diffusion equation by the second law of Fick, and by using finite difference method, the humidity diffusion equation of the inner of the rock mass is deduced under the influence of temperature; Based on rock elastic-plastic constitutive theory, respectively is derived to calculate the temperature-humidity under the action of strain caused by various factors, and then deduced the thermal humidity-stress coupled incremental elastoplastic constitutive equations by the incremental strain theory; finally combined the actual parameters of a site, use derivation of elastoplastic constitutive equation to calculate the area under the action of temperature-humidity stress field, contrast the site measured data, found that equation are accord with actual trend.4.Based on the theory above, analysis of the mechanism of action of two parallel cracks, and calculated the stress fieldunder the action of temperature-humidity stress field, founding the rule about stress field of crack combination with the example.5.Established the calculation model of tunnel portal section of weak surrounding rock in a given area, based on the working condition of the model points are numerically simulated, analyzed the temperature or temperature-humidity fields, under the action of model with and without crack, the single crack and two parallel, close and parallel distance parallel fracture stress field, displacement field distribution; and elastic-plastic boundary can be determined in the crack tip stress influence of the double parallel cracks; at the last, calculated the stress field and deformation of single crack for 35 years.6. In view of the surrounding rock under high temperature and high humidity environment, design of heat resistance, moisture fiber concrete to improve the stability of surrounding rock, conduct field test. In the construction site in accordance with three different ratio (steel fiber, glass fiber respectively 1:5,5:1,3:3) mix concrete, and concrete can be divided into two parts, one part is sent to the construction site for injection, one part is produced as test block; And on the basis of climate change rule, carries on the abnormal condition of steam curing; construction site measurement and test block test data, the monitoring found that the mixed fiber had effect on the deterioration of concrete caused by high temperature and humidity. |
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