砂砾地层盾构隧道受力光弹试验
|
摘要
为满足城市地下管廊、城际快速地下交通网的建设需求,中国隧道工程的应用率与日俱增。砂砾地层因黏聚力较低,与其他地质条件地层相比工程特性明显。在分析类似地质情况下的盾构隧道受力时,连续性介质假设已不能满足实际需求,应从非连续介质角度分析隧道及其周围岩石介质的受力分布。通过光弹试验观测砂砾地层中隧道-围岩系统内的力链强弱及其分布形式,并应用数字图像处理方法提取力链信息。在光弹颗粒中设置圆形管道以模拟盾构隧道,并通过改变内置管道的直径大小,改变上部及侧部载荷大小,以及在管道底部进行光弹颗粒释放,来分析砂砾地层中隧道直径、埋深变化及隧道底部的地层破坏、流动对隧道-围岩系统中力链分布的影响。利用颗粒元软件PFC对试验过程进行数值模拟,对比分析模拟结果与试验结果以验证试验的可靠性。结果表明:力链是砂砾地层与隧道之间载荷传递的主要方式,围岩与隧道间的接触力分布具有非对称性;隧道的椭圆化程度及其周围砂砾岩层中的力链密度,均随着隧道直径和埋深的增加而增大;当砂砾地层破坏、流动时,隧道-围岩系统内的力链也被破坏并重新分布,地层内维持系统稳定的"环状"强力链退化成为"拱形"强力链,系统自稳性产生破坏,此时应采取措施强化系统的稳定性。
To satisfy the construction demand for urban underground tube corridor and intercity rapid underground transportation network, the application rate of tunnel engineering in China has been increasing daily. Because of low cohesiveness, the engineering characteristics of gravel strata compared with the rock stratum are obvious. In the analysis of tunnels under similar geological conditions, the assumption of a continuous medium cannot satisfy the actual demand. Thus, the stress distribution in the tunnel and its surrounding rock should be analyzed from the perspective of a discontinuous medium. In this paper, a photoelastic experiment was employed to study the strength and distribution of the force chain in a tunnel-surrounding rock system in the gravel strata and extract the chain information using digital image processing. A round-tunnel simulation shield was set up in the photoelastic particles. By changing the diameter of the built-in pipeline and the size of the upper and side loads, the photoelastic particles at the bottom of the pipeline were released. The tunnel diameter of the gravel layer was analyzed. The influence of the changes in the burial depth and damage flow of the surrounding rock at the bottom of the tunnel on the distribution of the force chain in the tunnel-surrounding rock system was investigated. Particle element software PFC was used to simulate the experimental process. The simulation and experimental results were analyzed and compared to verify the reliability of the methods. The results show that force chain is the main method of load transfer between the gravel strata and tunnel. The contact-force distribution between the surrounding rock and tunnel is asymmetrical. The elliptical degree of the tunnel and the force-chain density in the surrounding sand and gravel strata are enhanced with the increase in the tunnel diameter and burial depth. The gravel strata are damaged and flow. The force chain in the tunnel-surrounding rock system is destroyed and redistributed. The "ring" strong force chain that maintains the system stability in the rock strata is reduced to an "arch" strong force chain. The stability of the system is damaged.
To satisfy the construction demand for urban underground tube corridor and intercity rapid underground transportation network, the application rate of tunnel engineering in China has been increasing daily. Because of low cohesiveness, the engineering characteristics of gravel strata compared with the rock stratum are obvious. In the analysis of tunnels under similar geological conditions, the assumption of a continuous medium cannot satisfy the actual demand. Thus, the stress distribution in the tunnel and its surrounding rock should be analyzed from the perspective of a discontinuous medium. In this paper, a photoelastic experiment was employed to study the strength and distribution of the force chain in a tunnel-surrounding rock system in the gravel strata and extract the chain information using digital image processing. A round-tunnel simulation shield was set up in the photoelastic particles. By changing the diameter of the built-in pipeline and the size of the upper and side loads, the photoelastic particles at the bottom of the pipeline were released. The tunnel diameter of the gravel layer was analyzed. The influence of the changes in the burial depth and damage flow of the surrounding rock at the bottom of the tunnel on the distribution of the force chain in the tunnel-surrounding rock system was investigated. Particle element software PFC was used to simulate the experimental process. The simulation and experimental results were analyzed and compared to verify the reliability of the methods. The results show that force chain is the main method of load transfer between the gravel strata and tunnel. The contact-force distribution between the surrounding rock and tunnel is asymmetrical. The elliptical degree of the tunnel and the force-chain density in the surrounding sand and gravel strata are enhanced with the increase in the tunnel diameter and burial depth. The gravel strata are damaged and flow. The force chain in the tunnel-surrounding rock system is destroyed and redistributed. The "ring" strong force chain that maintains the system stability in the rock strata is reduced to an "arch" strong force chain. The stability of the system is damaged.
引文
[1] 钱七虎,陈晓强.国内外地下综合管线廊道发展的现状、问题及对策[J].地下空间与工程学报,2007,3(2):191-194. QIAN Qi-hu, CHEN Xiao-qiang. Situation, Problems and Countermeasures of Utility Tunnel Development in China and Abroad [J]. Chinese Journal of Underground Space and Engineering, 2007, 3 (2): 191-194.
[2] 洪开荣.我国隧道及地下工程近两年的发展与展望[J].隧道建设,2017,37(2):123-134. HONG Kai-rong. Development and Prospects of Tunnels and Underground Works in China in Recent Two Years [J]. Tunnel Construction, 2017, 37 (2):123-134.
[3] 黄黔.盾构法隧道施工中的力学和控制论[M].北京:科学出版社,2014. HUANG Qian. Mechanics and Control Theory in Shield Tunnel Construction [M]. Beijing: Science Press, 2014.
[4] 钱勇进,朱伟,闵凡路,等.砂卵石地层中泥膜支护土压盾构施工试验[J].中国公路学报,2017,30(8):210-215. QIAN Yong-jin, ZHU Wei, MIN Fan-lu, et al. Test of Construction Method of EPB Shield with Filter Membrane Supporting in Sand and Cobble Stratum [J]. China Journal of Highway and Transport, 2017, 30 (8): 210-215.
[5] 吴跃东,罗如平,王维春.南京地区砂砾卵石土压实特性的离散元模拟[J].中国公路学报,2015,28(4):13-18,26. WU Yue-dong, LUO Ru-ping, WANG Wei-chun. DEM Simulation on Nanjing Sand-gravel-cobble Mixture Compaction Characteristics [J]. China Journal Highway and Transport, 2015, 28 (4): 13-18, 26.
[6] 宋克志,汪波,孔恒,等.无水砂卵石地层土压盾构施工泡沫技术研究[J].岩石力学与工程学报,2005,24(13):2327-2332. SONG Ke-zhi, WANG Bo, KONG Heng, et al. Study on FOAM Technology During Shield Excavation in Sandy Cobble Bed Without Water [J] Chinese Journal of Rock Mechanics and Engineering, 2005, 24 (13): 2327-2332.
[7] 范建国,方勇,张雪金,等.砂卵石地层圆形隧道施工引起的土体移动特征[J].地下空间与工程学报,2017,13(6):1599-1607. FAN Jian-guo, FANG Yong, ZHANG Xue-jin, et al. Ground Movement Induced by Shield Tunnel Construction in Sandy Cobble Stratum [J]. Chinese Journal of Underground Space and Engineering, 2017, 13 (6): 1599-1607.
[8] 王俊,何川,李栋林,等.砂卵石地层地下水对盾构隧道影响的离散元流固耦合分析[J].隧道建设,2016,36(6):710-716. WANG Jun, HE Chuan, LI Dong-lin, et al. Discrete Element Solid-fluid Coupling Analysis of Influence of Groundwater on Shield Tunnel in Sandy-cobble Strata [J]. Tunnel Construction, 2016, 36 (6): 710-716.
[9] 杨荣伟,程晓辉.光弹颗粒材料的直剪实验研究[J].岩土力学,2009,30(增):103-109. YANG Rong-wei, CHENG Xiao-hui. Direct Shear Experiments of Photoelastic Granular Materials [J]. Rock and Soil Mechanics, 2009, 30 (S): 103-109.
[10] JU Y, WANG L, XIE H P, et al. Visualization and Transparentization of the Structure and Stress Field of Aggregated Geomaterials Through 3D Printing and Photoelastic Techniques [J]. Rock Mechanics Rock Engineering, 2017, 50: 1383-1407.
[11] 孙其诚,王光谦.颗粒流动力学及其离散模型述评[J].力学进展,2008,38(1):87-100. SUN Qi-cheng, WANG Guang-qian. Review on Granular Flow Dynamics and Its Discrete Element Method [J]. Advances in Mechanics, 2008, 38 (1): 87-100.
[12] 王光谦,孙其诚.颗粒物质及其多尺度结构统计规律[J].工程力学,2009,26(增2):1-7. WANG Guang-qian, SUN Qi-cheng. Granular Matter and the Scaling Laws [J]. Engineering Mechanics, 2009, 26 (S2): 1-7.
[13] 孙其诚,程晓辉,季顺迎,等.岩土类颗粒物质宏-细观力学研究进展[J].力学进展,2011,41(3):351-371. SUN Qi-cheng, CHENG Xiao-hui, JI Shun-ying, et al. Advances in Micro-macro Mechanics of Granular Soil Materials [J]. Advances in Mechanics, 2011, 41 (3): 351-371.
[14] 王金安,韩现刚,任鹏召.综放开采顶煤介质状态演化的特征识别[J].煤炭学报,2016,41(增1):1-6. WANG Jin-an, HAN Xian-gang, REN Peng-zhao. The Identification of the Damage State Evolution in Top Coal Caving Mining [J]. Journal of China Coal Society, 2016, 41 (S1): 1-6.
[15] 王金安,韩现刚,庞伟东,等.综放开采顶煤与覆岩力链结构及演化光弹试验研究[J].工程科学学报,2017,39(1):13-22. WANG Jin-an, HAN Xian-gang, PANG Wei-dong, et al. Photoelastic Experimental Study on the Force Chain Structure and Evolution in Top Coal [J]. Chinese Journal of Engineering, 2017, 39 (1): 13-22.
[16] 王金安,庞伟东,梁超,等.一种双向颗粒流动光弹实验装置:中国,CN204556449U[P].2015-08-12. WANG Jin-an, PANG Wei-dong, LIANG Chao, et al. A Photoelastic Experimental Apparatus for Biaxial Loading and Bilateral Flowing of Particles: China, CN204556449U [P]. 2015-08-12.
[17] 黄威然,杨书江.砂与砂砾地层盾构工程技术[M].北京:中国建筑工业出版社,2012. HUANG Wei-ran, YANG Shu-jiang. Shield and Sand Engineering Technology of Sand and Grit Stratum [M]. Beijing: China Architecture & Building Press, 2012.
[18] MAJMUDAR T S, BEHRINGER R P. Contact Force Measurements and Stress-induced Anisotropy in Granular Materials [J]. Nature, 2005, 435 (2): 1079-1082.
[19] 天津大学材料力学组.光弹性原理及测试技术[M].北京:科学出版社,1980. Material Mechanics Group, Tianjin University. Photoelastic Principle and Test Technology [M]. Beijing: Science Press, 1980.
[20] HOWELL D W. Stress Distribution and Fluctuations in Static and Quasi-static Granular Systems [D]. Durham: Duke University, 1999.
[21] 陈再现,陈芍桥,吴斌,等.基于静力相似的缩尺拟动力试验方法数值模拟研究[J].土木工程学报,2014,47(增2):307-311. CHEN Zai-xian, CHEN Shao-qiao, WU Bin, et al. The Numerical Simulation of Pseudo-dynamic Test Method for Scale Model Based on the Static Similar Condition [J]. China Civil Engineering Journal, 2014, 47 (S2): 307-311.
[2] 洪开荣.我国隧道及地下工程近两年的发展与展望[J].隧道建设,2017,37(2):123-134. HONG Kai-rong. Development and Prospects of Tunnels and Underground Works in China in Recent Two Years [J]. Tunnel Construction, 2017, 37 (2):123-134.
[3] 黄黔.盾构法隧道施工中的力学和控制论[M].北京:科学出版社,2014. HUANG Qian. Mechanics and Control Theory in Shield Tunnel Construction [M]. Beijing: Science Press, 2014.
[4] 钱勇进,朱伟,闵凡路,等.砂卵石地层中泥膜支护土压盾构施工试验[J].中国公路学报,2017,30(8):210-215. QIAN Yong-jin, ZHU Wei, MIN Fan-lu, et al. Test of Construction Method of EPB Shield with Filter Membrane Supporting in Sand and Cobble Stratum [J]. China Journal of Highway and Transport, 2017, 30 (8): 210-215.
[5] 吴跃东,罗如平,王维春.南京地区砂砾卵石土压实特性的离散元模拟[J].中国公路学报,2015,28(4):13-18,26. WU Yue-dong, LUO Ru-ping, WANG Wei-chun. DEM Simulation on Nanjing Sand-gravel-cobble Mixture Compaction Characteristics [J]. China Journal Highway and Transport, 2015, 28 (4): 13-18, 26.
[6] 宋克志,汪波,孔恒,等.无水砂卵石地层土压盾构施工泡沫技术研究[J].岩石力学与工程学报,2005,24(13):2327-2332. SONG Ke-zhi, WANG Bo, KONG Heng, et al. Study on FOAM Technology During Shield Excavation in Sandy Cobble Bed Without Water [J] Chinese Journal of Rock Mechanics and Engineering, 2005, 24 (13): 2327-2332.
[7] 范建国,方勇,张雪金,等.砂卵石地层圆形隧道施工引起的土体移动特征[J].地下空间与工程学报,2017,13(6):1599-1607. FAN Jian-guo, FANG Yong, ZHANG Xue-jin, et al. Ground Movement Induced by Shield Tunnel Construction in Sandy Cobble Stratum [J]. Chinese Journal of Underground Space and Engineering, 2017, 13 (6): 1599-1607.
[8] 王俊,何川,李栋林,等.砂卵石地层地下水对盾构隧道影响的离散元流固耦合分析[J].隧道建设,2016,36(6):710-716. WANG Jun, HE Chuan, LI Dong-lin, et al. Discrete Element Solid-fluid Coupling Analysis of Influence of Groundwater on Shield Tunnel in Sandy-cobble Strata [J]. Tunnel Construction, 2016, 36 (6): 710-716.
[9] 杨荣伟,程晓辉.光弹颗粒材料的直剪实验研究[J].岩土力学,2009,30(增):103-109. YANG Rong-wei, CHENG Xiao-hui. Direct Shear Experiments of Photoelastic Granular Materials [J]. Rock and Soil Mechanics, 2009, 30 (S): 103-109.
[10] JU Y, WANG L, XIE H P, et al. Visualization and Transparentization of the Structure and Stress Field of Aggregated Geomaterials Through 3D Printing and Photoelastic Techniques [J]. Rock Mechanics Rock Engineering, 2017, 50: 1383-1407.
[11] 孙其诚,王光谦.颗粒流动力学及其离散模型述评[J].力学进展,2008,38(1):87-100. SUN Qi-cheng, WANG Guang-qian. Review on Granular Flow Dynamics and Its Discrete Element Method [J]. Advances in Mechanics, 2008, 38 (1): 87-100.
[12] 王光谦,孙其诚.颗粒物质及其多尺度结构统计规律[J].工程力学,2009,26(增2):1-7. WANG Guang-qian, SUN Qi-cheng. Granular Matter and the Scaling Laws [J]. Engineering Mechanics, 2009, 26 (S2): 1-7.
[13] 孙其诚,程晓辉,季顺迎,等.岩土类颗粒物质宏-细观力学研究进展[J].力学进展,2011,41(3):351-371. SUN Qi-cheng, CHENG Xiao-hui, JI Shun-ying, et al. Advances in Micro-macro Mechanics of Granular Soil Materials [J]. Advances in Mechanics, 2011, 41 (3): 351-371.
[14] 王金安,韩现刚,任鹏召.综放开采顶煤介质状态演化的特征识别[J].煤炭学报,2016,41(增1):1-6. WANG Jin-an, HAN Xian-gang, REN Peng-zhao. The Identification of the Damage State Evolution in Top Coal Caving Mining [J]. Journal of China Coal Society, 2016, 41 (S1): 1-6.
[15] 王金安,韩现刚,庞伟东,等.综放开采顶煤与覆岩力链结构及演化光弹试验研究[J].工程科学学报,2017,39(1):13-22. WANG Jin-an, HAN Xian-gang, PANG Wei-dong, et al. Photoelastic Experimental Study on the Force Chain Structure and Evolution in Top Coal [J]. Chinese Journal of Engineering, 2017, 39 (1): 13-22.
[16] 王金安,庞伟东,梁超,等.一种双向颗粒流动光弹实验装置:中国,CN204556449U[P].2015-08-12. WANG Jin-an, PANG Wei-dong, LIANG Chao, et al. A Photoelastic Experimental Apparatus for Biaxial Loading and Bilateral Flowing of Particles: China, CN204556449U [P]. 2015-08-12.
[17] 黄威然,杨书江.砂与砂砾地层盾构工程技术[M].北京:中国建筑工业出版社,2012. HUANG Wei-ran, YANG Shu-jiang. Shield and Sand Engineering Technology of Sand and Grit Stratum [M]. Beijing: China Architecture & Building Press, 2012.
[18] MAJMUDAR T S, BEHRINGER R P. Contact Force Measurements and Stress-induced Anisotropy in Granular Materials [J]. Nature, 2005, 435 (2): 1079-1082.
[19] 天津大学材料力学组.光弹性原理及测试技术[M].北京:科学出版社,1980. Material Mechanics Group, Tianjin University. Photoelastic Principle and Test Technology [M]. Beijing: Science Press, 1980.
[20] HOWELL D W. Stress Distribution and Fluctuations in Static and Quasi-static Granular Systems [D]. Durham: Duke University, 1999.
[21] 陈再现,陈芍桥,吴斌,等.基于静力相似的缩尺拟动力试验方法数值模拟研究[J].土木工程学报,2014,47(增2):307-311. CHEN Zai-xian, CHEN Shao-qiao, WU Bin, et al. The Numerical Simulation of Pseudo-dynamic Test Method for Scale Model Based on the Static Similar Condition [J]. China Civil Engineering Journal, 2014, 47 (S2): 307-311.