【作者】 张果；

【导师】 许模；

【作者基本信息】 成都理工大学 ， 地质工程， 2011， 硕士

【摘要】 21世纪以来,随着经济建设快速发展以及西部大开发战略的实施,在水电工程、交通工程、跨流域调水工程中,越岭隧道方案被大量采用并逐渐朝深埋、特长方向发展。随着隧洞埋深增大,隧洞的高外水压问题越来越突出。隧洞高外水压力的存在导致施工运营过程中经常出现大规模塌方、涌突水、衬砌破裂等工程事故。事故一旦发生,轻则影响施工,损坏机械,增加工程造价,重则造成国家财产损失、人员严重伤亡。隧洞高外水压力问题已成为当下隧洞设计和施工中很关键且无法回避的问题,引起社会各界的极大关注。通过查阅隧洞外水压力相关性文献,归纳总结国内外相关研究成果,认识到围岩渗透性是隧洞外水压力的重要影响因素,但目前为止关于围岩渗透性与隧洞外水压力的相关性研究大多是经验性的,不全面的。基于此,本文拟定“围岩渗透性与隧洞外水压力的相关性探讨”为选题,围绕无压隧洞外水压力问题,采用数值模拟法,系统地探讨了围岩渗透性对隧洞外水压力的影响机制和影响程度等理论,并与前人围岩渗透性与隧洞外水压力相关性的研究成果进行比对,初步建立了围岩渗透性与无压隧洞外水压力折减系数的对应关系:隧洞结构确定的均质围岩中:(1)同一水头高度下,围岩渗透性从强变弱,隧洞外水压力从大变小,隧洞外水压力折减系数从大变小。(2)围岩渗透性不变的情况下,水头高度越小,隧洞外水压力越小,隧洞外水压力折减系数越小。隧洞结构确定的非均质围岩中:(1)均质围岩中围岩渗透系数与隧洞外水压力折减系数的相关性同样适用于非均质围岩。(2)渗透系数规律性变化的围岩中隧洞外水压力的折减系数与等效渗透系数的围岩中隧洞外水压力的折减系数是有差别的。(3)存在透镜体的围岩中,随着水头高度的变化,渗透系数不同的透镜体对隧洞外水压力的影响效果是有差别的。更多还原

【Abstract】 In the 21st century , with the rapid development of economic construction and the implementation of the western development strategy ,watershed tunnel scheme is adopted in great quantities and towards deeper lying,extra-large direction in hydropower engineering, transportation engineering、inter-basin diversion project. Along with the increase of buried depth, the high external water pressure problem becomes more and more serious .The existence of high external water pressure often leads large-scale landslide, water gushing and lining fracture event. Once happen, it will influence the construction, damage machinery, increase the cost and even cause heavy casualties. Now the high external water pressure has become an important and unavoidable problem in the design and construction of the tunnel, and has evoked enormous attention.Based on the previous research, it is found that the permeability of surrounding rock largely influences the external water pressure of the tunnel. Until now the correlation studies between permeability of surrounding rock and the external water pressure of tunnel are mostly empirical, not comprehensive. So the topic“Discussion of the correlation between permeability of surrounding rock and the external water pressure of tunnel”is selected.Concentrated on the question of external water pressure , the basic influence mechanism and the theory of influencing degree about the permeability of surrounding rock to the external water pressure of non-pressure tunnel is systematically studied in this paper. Compared to the previous research achievement, the corresponding relationship between the permeability of surrounding rock and the external water pressure of non-pressure tunnel has been initial established. The main conclusions are as follows: (1) In the homogeneous rock , when the tunnel structure is determined and the total head is the same , the smaller the permeability coefficient, ,the smaller the external water pressure and its reduction coefficient.(2) In the homogeneous rock, when the tunnel structure and the permeability coefficient is determined, the smaller the total head, ,the smaller the external water pressure and its reduction coefficient.In the heterogeneous rock,(1)The rule in the homogeneous rock is suitable to the heterogeneous rock.(2)When the permeability coefficient changes regularly, the reduction coefficient of external water pressure is different to the coefficient in equivalent permeable rock .(3) When lenticle exists in the rock, as the head increases, the effect of different permeability of the lenticle to external water pressure is different.更多还原