發(fā)布時(shí)間：2018-05-26 01:53

  本文選題：軟巖隧洞 + 應(yīng)變強(qiáng)化　； 參考：《華僑大學(xué)》2017年碩士論文

【摘要】：在隧洞開挖過程中,兩幫收斂和底板向上鼓起等成為常見的工程災(zāi)害。通過圍巖性質(zhì)、力學(xué)特性和變形機(jī)制等,進(jìn)行深埋軟巖隧洞圍巖力學(xué)狀態(tài)的解析研究。本文基于冪強(qiáng)化-理想塑性本構(gòu)模型和平面應(yīng)變理論下考慮擴(kuò)容性能的巖土體中主應(yīng)力計(jì)算式,求解出Drucker-Prager強(qiáng)度準(zhǔn)則下軟巖隧洞的三維彈塑性解。在恒定應(yīng)力場作用下,借助非關(guān)聯(lián)流動法則、Burgers蠕變模型計(jì)算深埋軟巖隧洞黏彈塑性蠕變解,從理論上闡釋了軟巖隧洞變形機(jī)制并深化了侯公羽的求解。將計(jì)算結(jié)果與軟巖(粘土巖)隧洞的實(shí)測數(shù)據(jù)進(jìn)行對比,發(fā)現(xiàn)本研究結(jié)果可較好的反映深埋軟巖隧洞長期時(shí)效變形。最后考慮有水條件下軟巖隧洞出現(xiàn)的吸水膨脹現(xiàn)象,基于改進(jìn)Burgers模型初步探討了軟巖隧洞吸水失穩(wěn)的力學(xué)問題。得出以下結(jié)論:1.冪強(qiáng)化-理想塑性模型能較好的描述深埋軟巖隧洞圍巖的力學(xué)狀態(tài),再考慮圍巖中主應(yīng)力與擴(kuò)容的影響,結(jié)果發(fā)現(xiàn)不考慮擴(kuò)容效應(yīng)的體積不可壓縮理論存在物理意義上的錯(cuò)誤,具有一定的局限性。2.隨著擴(kuò)容角的增加,深埋軟巖隧洞的圍巖應(yīng)力逐漸增大,塑性區(qū)半徑呈遞增的趨勢,這與參數(shù)的物理意義一致。隧洞圍巖位移明顯增加且發(fā)展變快,隧洞周邊位移對冪強(qiáng)化參數(shù)的敏感性越高。3.應(yīng)變強(qiáng)化效應(yīng)和擴(kuò)容特性二者對深埋軟巖隧洞圍巖的應(yīng)力狀態(tài)具有一定的協(xié)同作用,增大擴(kuò)容角或冪強(qiáng)化指數(shù),隧洞圍巖位移的敏感性隨之增強(qiáng),考慮擴(kuò)容或應(yīng)變強(qiáng)化效應(yīng)的軟巖隧洞變形明顯大于不考慮的情況。4.不論是否考慮吸水效應(yīng)的影響,對于深埋軟巖隧洞圍巖的長期時(shí)效變形,隨著冪強(qiáng)化指數(shù)值的增大,應(yīng)變強(qiáng)化效應(yīng)加強(qiáng),洞壁蠕變位移量增大,且隧洞圍巖的蠕變行為對時(shí)間的敏感性越高。擴(kuò)容角越大,洞壁位移明顯增加且發(fā)展變快。在富水條件下,顧及吸水率影響的深埋軟巖隧洞變形明顯大于不考慮的情況,對圍巖長期穩(wěn)定不利。本文針對深埋軟巖隧洞的圍巖力學(xué)問題,基于理論研究了該類隧洞的變形機(jī)制,探索了不同遇水條件下隧洞長期時(shí)效變形。解析結(jié)果可作為修筑軟巖隧洞的數(shù)學(xué)、物理和力學(xué)理論依據(jù)。
[Abstract]:In the process of tunnel excavation, the convergence of two sides and the upwelling of bottom plate become common engineering disasters. Based on the properties of surrounding rock, mechanical properties and deformation mechanism, the mechanical state of surrounding rock in deep buried soft rock tunnel is studied. Based on the power hardening ideal plastic constitutive model and the plane strain theory the three dimensional elastoplastic solution of soft rock tunnel under Drucker-Prager strength criterion is obtained. Under the action of constant stress field, the viscoelastic-plastic creep solution of deep buried soft rock tunnel is calculated by the Burgers creep model with the aid of non-associated flow rule, and the deformation mechanism of soft rock tunnel is explained theoretically and the solution of Hou Gongyu is deepened. By comparing the calculated results with the measured data of soft rock (clay rock) tunnels, it is found that the results of this study can well reflect the long-term aging deformation of deep buried soft rock tunnels. Finally, considering the phenomenon of water absorption and expansion in soft rock tunnel under the condition of water, the mechanical problems of water absorption instability of soft rock tunnel are discussed based on the improved Burgers model. Draw the following conclusion: 1. The power-hardening ideal plastic model can well describe the mechanical state of the surrounding rock in deep buried soft rock tunnel, and then consider the influence of principal stress and expansion in surrounding rock. The result shows that the volume incompressibility theory without considering the expansion effect has a physical error. Has some limitations. With the increase of expansion angle, the surrounding rock stress of deep buried soft rock tunnel increases gradually, and the radius of plastic zone increases, which is consistent with the physical meaning of the parameters. The displacement of surrounding rock of tunnel increases obviously and develops faster, and the sensitivity of surrounding displacement of tunnel to power strengthening parameter is higher. 3. The strain strengthening effect and the expansion characteristic have some synergistic effect on the stress state of the surrounding rock of the deep buried soft rock tunnel. The sensitivity of the surrounding rock displacement of the tunnel increases with the increase of the expansion angle or the exponent of power strengthening. The deformation of soft rock tunnel considering capacity expansion or strain strengthening effect is obviously larger than that without consideration. Whether or not the effect of water absorption is considered or not, for the long-term aging deformation of the surrounding rock of deep buried soft rock tunnel, with the increase of power strengthening exponent, the strain strengthening effect is strengthened, and the creep displacement of tunnel wall increases. The creep behavior of tunnel surrounding rock is more sensitive to time. The larger the expansion angle, the more the wall displacement increases and the development becomes faster. Under the condition of rich water, the deformation of deep buried soft rock tunnel considering the influence of water absorption is obviously larger than that without consideration, which is unfavorable to the long-term stability of surrounding rock. In this paper, the deformation mechanism of the deep buried soft rock tunnel is studied based on the theory, and the long-term aging deformation of the tunnel under different water conditions is explored. The analytical results can be used as the theoretical basis of mathematics, physics and mechanics for the construction of soft rock tunnel.
【學(xué)位授予單位】：華僑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：U451.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 朱傳奇;殷志強(qiáng);李傳明;劉萬榮;范浩;;考慮應(yīng)變硬化和擴(kuò)容特性的巷道圍巖穩(wěn)定性分析[J];中國安全科學(xué)學(xué)報(bào);2016年06期

2 左清軍;吳立;李波;陸中s，

本文編號：1935487