Research On Application And Forced Mechanism Of Shaft Lining Considering The Effect Of Temperature And Draining Vertical Additional Force

Since the shaft lining in deep alluvium is under complex work environment, the shaft lining mechanical state is inevitably affected by the environment factors changing. Temperature and groundwater are the main factors that affect the mechanical state of the working vertical shaft. The shaft lining fracture is caused by the vertical additional stress, which is from the changes of temperature and groundwater. So it is very important to research the effect of the temperature and the groundwater change on the shaft lining mechanical state, and analyze the shaft lining mechanics state evolution law under different conditions of temperature and groundwater. And these have very vital significance for further understanding the shaft lining fracture mechanism, prevention rupture, and perfecting the shaft structure design theory. In this thesis, the major researches are summarized in the following.(1)On the basis of depth analysis of shaft lining work loads in deep alluvium, the internal force calculation model of shaft lining is built by the thermodynamics and the elastic mechanics theory in consideration of temperature, horizontal lateral pressure, and draining vertical additional force of shaft lining. With the consideration of temperature stress and draining vertical additional force, the internal force elasticity analytic solution is deduced and the basis is provided for structure design and stability evaluation of shaft lining. With the internal force analysis of burst shaft lining, the range of draining vertical additional force is gotten by the inversion analysis of structure design theory on the premise of considering temperature effect. Through the calculation and analysis of the vertical stress component produce by the temperature, horizontal lateral pressure, gravity load and draining vertical additional force, the results show that the draining vertical additional force is the most important factor that leads to shaft lining fracture and the temperature stress is the secondary factor causing shaft lining rupture. The draining vertical additional force range of Jining mining area is obtained by inversion analysis of Jining No.3 Coal Mine shaft lining considering the temperature stress. According to the proximity of shaft structure and stratum between Jining No.2 Coal Mine and Jining No.3 Coal Mine, the safety of Jining No.2 Coal Mine shaft lining is predicted. Combining with the underground water level monitoring information, the conclusion can be obtained that Jining No.2 Coal Mine shaft lining is in the safe state.(2)Based on deep analysis the effect of temperature and shear action between soil and shaft lining caused by bottom aquifer draining, the elastic-plastic calculation models of temperature stress and bottom aquifer draining vertical additional stress are set up, respectively. And the calculation formulas of shaft lining vertical additional stress are deduced. The example analysis shows the vertical temperature additional stress increases with the depth of shaft lining, and the peak is on the boundary between deep alluvium and bedrock. This calculation result is smaller than the result of plane strain model calculating. But this calculation result is more accord with engineering practice because this model considers shear displacement between soil and shaft lining. The calculation results of draining vertical additional stress show that the additional stress is increasing with the compression quantity of bottom aquifer and the groundwater head drop increases. And it is maximized at the boundary of elastic-plastic, and then decreases, on the boundary of overburden and bedrock it decreases to zero. By calculating temperature stress and draining vertical additional stress, the stability of shaft lining can be further analyzed and the theoretical basis can be provided for the prediction and forecast of shaft lining mechanics state.(3)The temperature-force coupling optimization inversion analysis method of draining vertical additional force is proposed on basis of monitoring shaft lining additional strain. And the draining vertical additional force change law is obtained by the temperature-force coupling simulation analysis, which is based on the measured strain data of auxiliary shaft lining in Jining No.3 Coal Mine. The vertical additional force increases gradually with draining time and shaft lining depth, and with the passage of time, the increase rate is more and more big. According to the average monthly amount of draining additional force obtained by the temperature and force coupling optimization adverse analysis, the fracture time of Jining No.3 Coal Mine auxiliary shaft lining is forecasted according to Coulomb-Navier criterion, and the prediction result is relative accordance with the numerical simulation result. So this method has high reliability to guide shaft lining stability analysis, and it has important practical value for the informatization construction and the management of shaft lining fracture.(4)By depth analysis of shaft lining stress and strain data measured, the dual role model of temperature on shaft lining stress is proposed. Namely, according to the high and low of shear strength between shaft lining and soil, the temperature effect on shaft lining stress has two kinds of model. One is temperature stress accumulation when the temperature rises and temperature stress release when the temperature reduces. The other is temperature stress release when the temperature rises and temperature stress accumulation when the temperature reduces. And the correctness of dual role model is verified by numerical simulation. The view can deepen to understand shaft lining fracture mechanism, and it is helpful to perfect the theory of shaft lining fracture. In the two different cases of high and low shear strength, under different water head drop and temperature the interaction is simulated between shaft lining and soil by using FLAC3 D, and the change rules of vertical additional force and vertical additional stress are obtained. When the shear strength is lower, under the condition of same water head drop, the vertical additional force is reduced with the rise of shaft lining temperature. Under the condition of the same head drop, the vertical stress of shaft lining is decreased with temperature rising, and increased with temperature decrease. When the shear strength is high, in the case of same head drop, the vertical additional force is increased with temperature rising. Under the condition of same head drop, the vertical stress of shaft lining is increased with temperature rising, and reduced with the temperature decreases.