炭质泥岩夹砂岩隧道大变形机理及控制措施研究
发布时间：2019-04-08 12:53
【摘要】：软岩大变形一直是困扰隧道工程界的一个重要问题,尤其是在软岩隧道变形机理方面,由于软岩岩性和工程地质条件的复杂性,通过传统的理论分析和经验判断不足以准确的掌握围岩的变形机制和变形规律,进而提出有效的变形控制措施。本文以“滨绥线牡丹江至绥芬河段扩能改造工程”的兴源隧道为依托,以软岩隧道大变形为背景,采用现场应力及变形监控量测、理论分析和有限元计算相结合的手段来分析隧道的大变形机理,并通过数值模拟手段对比分析优选出最优的变形控制措施。最后通过突变理论来分析隧道施工过程中的极限位移,并根据计算结果运用当前工程界普遍使用的三级管理机制对隧道围岩变形控制基准进行分级,提出了不同埋深下隧道的变形控制基准。论文的主要工作和成果如下:(1)结合现场监控量测数据分析兴源隧道变形与支护受力之间的相互作用关系和特征。分析结果表明,围岩变形持续时间长,具有很强的流变性;受软弱夹层及岩层走向、倾向的影响,围岩变形和支护受力表现出明显的不对称性。(2)通过将现场监控量测分析与工程地质资料相结合,得出兴源隧道围岩大变形属于围岩岩性控制类型,地层岩性、高地应力、软弱夹层和地下水是围岩产生大变形的重要影响因素,其变形机理是高地应力下软岩的塑性流变、围岩的弯曲变形以及夹层的软化共同作用的结果。(3)根据软岩大变形机理分析的研究结果,有针对性的提出了不同的变形控制措施,并通过有限元数值模拟手段分别对每种变形控制措施进行优选,如采用不同台阶长度、不同开挖进尺、不同台阶高度、不同锁脚锚管以及不同纵向连接形式等。最终通过比选得出最优变形控制措施,宜采用5 m台阶长度、0.5 m开挖进尺、3.5 m台阶高度、上台阶采用下斜30°锁脚锚管、中台阶采用下斜15°锁脚锚管、纵向连接则采用14号槽钢。(4)通过对尖点突变理论的应用,分别计算不同应力释放率下隧道洞周关键点的塑性应变值,然后利用突变判据?来寻找塑性应变的突变点,从而确定围岩变形突变所对应的应力释放率,并以此作为围岩变形的极限状态。通过计算得出,当应力释放率达到70%时,围岩稳定性发生突变,进入塑性流动阶段,当应力释放率在45%与70%之间时,围岩处于塑性发展阶段,而在此之前围岩尚处于弹性变形阶段。(5)根据极限位移解答,以70%应力释放率为基准,运用当前工程界普遍使用的三级管理机制对隧道围岩变形控制基准进行分级,建立了不同埋深(50 m、100 m、150m)情况下的隧道围岩变形控制基准。
[Abstract]:Large deformation of soft rock has always been an important problem in tunnel engineering, especially in the deformation mechanism of soft rock tunnel, because of the complexity of soft rock lithology and engineering geological conditions. Through the traditional theoretical analysis and empirical judgment, it is not enough to grasp the deformation mechanism and deformation law of the surrounding rock accurately, and then put forward the effective deformation control measures. Based on the Xingyuan Tunnel in the Mudanjiang-Suifenhe Section of the Binsui-Sui-Sui Line and the large deformation of the soft rock tunnel, the field stress and deformation monitoring and measurement are adopted in this paper. The large deformation mechanism of tunnel is analyzed by the combination of theoretical analysis and finite element calculation, and the optimal deformation control measures are selected by comparing and analyzing the numerical simulation method. Finally, the ultimate displacement in tunnel construction process is analyzed by catastrophe theory. According to the calculation results, the control datum of surrounding rock deformation of tunnel is classified by using the three-level management mechanism commonly used in the current engineering field. The deformation control datum of tunnel under different depth is put forward. The main work and achievements of this paper are as follows: (1) the relationship and characteristics between deformation and supporting force of Xingyuan tunnel are analyzed based on field monitoring and measurement data. The results show that the deformation of the surrounding rock is of long duration and has a strong rheological property. Under the influence of weak interlayer, rock strike and tendency, the deformation of surrounding rock and supporting force show obvious asymmetry. (2) through the combination of on-site monitoring and analysis with engineering geological data, It is concluded that the large deformation of surrounding rock of Xingyuan tunnel belongs to the controlling type of surrounding rock lithology, formation lithology, high in-situ stress, weak interlayer and groundwater are the important influencing factors of large deformation of surrounding rock, and its deformation mechanism is plastic rheology of soft rock under high in-situ stress. (3) according to the research results of the mechanism analysis of large deformation of soft rock, different deformation control measures are put forward according to the results of the joint action of the bending deformation of surrounding rock and the softening of interlayer. Each deformation control measure is optimized by means of finite element numerical simulation, such as adopting different step length, different excavation length, different step height, different locking anchor pipe and different longitudinal connection forms, etc. Finally, the optimal deformation control measures can be obtained by comparing and selecting the optimal deformation control measures: 5 m step length, 0.5 m excavation scale, 3.5 m step height, 30 掳downward slope locking anchor pipe for upper step and 15 掳lock pin anchor pipe for middle step. Longitudinal connection adopts 14 # channel steel. (4) through the application of cusp catastrophe theory, the plastic strain values of the key points around the tunnel under different stress release rates are calculated respectively, and then the catastrophe criterion is used. In order to find the mutation point of plastic strain, the stress release rate corresponding to the sudden deformation of surrounding rock is determined, which is regarded as the limit state of the deformation of surrounding rock. The results show that when the stress release rate reaches 70%, the stability of the surrounding rock changes abruptly and enters the plastic flow stage. When the stress release rate is between 45% and 70%, the surrounding rock is in the plastic development stage. Before this, the surrounding rock is still in the elastic deformation stage. (5) according to the limit displacement solution, according to the 70% stress release rate as the benchmark, the control datum of tunnel surrounding rock deformation is classified by using the three-level management mechanism commonly used in the current engineering circles. The deformation control datum of tunnel surrounding rock with different buried depth (50m, 100m, 150m) is established.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4
[Abstract]:Large deformation of soft rock has always been an important problem in tunnel engineering, especially in the deformation mechanism of soft rock tunnel, because of the complexity of soft rock lithology and engineering geological conditions. Through the traditional theoretical analysis and empirical judgment, it is not enough to grasp the deformation mechanism and deformation law of the surrounding rock accurately, and then put forward the effective deformation control measures. Based on the Xingyuan Tunnel in the Mudanjiang-Suifenhe Section of the Binsui-Sui-Sui Line and the large deformation of the soft rock tunnel, the field stress and deformation monitoring and measurement are adopted in this paper. The large deformation mechanism of tunnel is analyzed by the combination of theoretical analysis and finite element calculation, and the optimal deformation control measures are selected by comparing and analyzing the numerical simulation method. Finally, the ultimate displacement in tunnel construction process is analyzed by catastrophe theory. According to the calculation results, the control datum of surrounding rock deformation of tunnel is classified by using the three-level management mechanism commonly used in the current engineering field. The deformation control datum of tunnel under different depth is put forward. The main work and achievements of this paper are as follows: (1) the relationship and characteristics between deformation and supporting force of Xingyuan tunnel are analyzed based on field monitoring and measurement data. The results show that the deformation of the surrounding rock is of long duration and has a strong rheological property. Under the influence of weak interlayer, rock strike and tendency, the deformation of surrounding rock and supporting force show obvious asymmetry. (2) through the combination of on-site monitoring and analysis with engineering geological data, It is concluded that the large deformation of surrounding rock of Xingyuan tunnel belongs to the controlling type of surrounding rock lithology, formation lithology, high in-situ stress, weak interlayer and groundwater are the important influencing factors of large deformation of surrounding rock, and its deformation mechanism is plastic rheology of soft rock under high in-situ stress. (3) according to the research results of the mechanism analysis of large deformation of soft rock, different deformation control measures are put forward according to the results of the joint action of the bending deformation of surrounding rock and the softening of interlayer. Each deformation control measure is optimized by means of finite element numerical simulation, such as adopting different step length, different excavation length, different step height, different locking anchor pipe and different longitudinal connection forms, etc. Finally, the optimal deformation control measures can be obtained by comparing and selecting the optimal deformation control measures: 5 m step length, 0.5 m excavation scale, 3.5 m step height, 30 掳downward slope locking anchor pipe for upper step and 15 掳lock pin anchor pipe for middle step. Longitudinal connection adopts 14 # channel steel. (4) through the application of cusp catastrophe theory, the plastic strain values of the key points around the tunnel under different stress release rates are calculated respectively, and then the catastrophe criterion is used. In order to find the mutation point of plastic strain, the stress release rate corresponding to the sudden deformation of surrounding rock is determined, which is regarded as the limit state of the deformation of surrounding rock. The results show that when the stress release rate reaches 70%, the stability of the surrounding rock changes abruptly and enters the plastic flow stage. When the stress release rate is between 45% and 70%, the surrounding rock is in the plastic development stage. Before this, the surrounding rock is still in the elastic deformation stage. (5) according to the limit displacement solution, according to the 70% stress release rate as the benchmark, the control datum of tunnel surrounding rock deformation is classified by using the three-level management mechanism commonly used in the current engineering circles. The deformation control datum of tunnel surrounding rock with different buried depth (50m, 100m, 150m) is established.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.4
【共引文献】
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