| Geological condition is the important factors in study on tunnel excavating disaster inevitably. From the aeolotropy of hard rock of tunnel engineering region, the stress distribution of several kinds of fault to the water gushing of tunnel, the type of geology disaster involved in macrocharacter, main control factors, disaster mechanism and control strategy in tunnel excavating are studied systematically in this thesis. The purpose is to establish a theory and technology method for forecast and decrease disaster in tunnel excavating.Based on the primacy aeolotropy rock, transversely isotropic rocks is hypothesized. With the theory of the stress distribution of the rockmass, disaster character of tunnel excavating in the type of transversely isotropic rocks is analyzed, and some strategy and technology of uniso-intensity support are raised.According to different types of disaster and mechanism of around rock mass under different faults, for study necessary, faults may be classified as three types, down fault, shift fault and reverse fault. From the stress status of down fault region, the type of disaster of tunnel excavating in jointed rock mass is defined as structural disaster. By means of the Block Theory, the tunnel destroy process can be studied, in which the block slip to spacing of tunnel can be described as three types: collapse, slip along single plane and slip along two planes, additionally the mechanics theory of these types of slip is studied systematically. On the basis of engineering rock mass classifications, the support system is advanced that the active support and passive one may be combined. In the light of the law that gravity stress is the main stress in the down fault region, the homo-tunnel principle is designed for section of tunnel. Furthermore, engineering application program is pose for control tunnel hazards.With the stress distribution of shift fault, the intercalated clay layer in the fault forming process and mechanism are discussed. Meanwhile, the intercalated clay layer distribution regular and some affecting factors, such as different rock combination, thickness of intercalated clay layer, the difference of rise-fall in hard rock of two stiffs, structural movement and so on, are studied systematically. The cause of forming water film and special mechanism is researched in depth on theory. It is obvious that the uncontinuous coefficient Kd affected mechanics properties greatly, and the water film make the strength of intercalated clay layer decrease more than one magnitude order.However, when the film disappear, the shear strength resumed to the initial value. The type of tunnel disaster is defined as strain lazards. Additionally, the net load F is gotten for forecasting the deform disaster of tunnel.For the purpose of getting the ground stress law in reverse fault region, it is very useful and important to use the study status of structure stress field as premise, moreover, a great quantity geology material can be synthesized to research the law. By means of the generalization of structure stress, the study model for structure stress generalization in tunnel engineering region is advanced. Additionally, author measured structure stress in a underground rock mass engineering region, and write 3D stress measure application program. The conclusion may be get that in the reverse fault region, the structure stress is high, as for hard rocks, rockburst is a typical geology disaster. Then rockburst is classified as six types according to the different character of underground engineering, besides the tunnel rockburst in reverse fault region. The rockburst mechanics model of different rock arranges of two walls in the fault, such as horizontal and longitudinal arrange, is raised and studied. The gotten law can supply the direction for rockburst forecast and control. With the main content of forecast rockburst, a feasible program and method for synthetical forecast rockburst in reverse fault region is represented in this thesis.On the basis of morphology, dual-porosity...
|
PDF Full Text Request