Citation: | WU Jianli, HU Xiewen, MEI Xuefeng, XU Zepeng, LUO Gang, HAN Mei. Dynamic response of RC slab with cushion layer composed of sandy soil to rockfall impact[J]. Hydrogeology & Engineering Geology, 2021, 48(1): 78-87. doi: 10.16030/j.cnki.issn.1000-3665.202004029 |
The structure of reinforced concrete (RC) slab with cushion layer composed of sandy soil is widely used in the prevention and control of high-level single rockfalls and rockfall group in mountainous areas. In order to study the impact attenuation law and the failure mode of RC slab under the rockfall load, an outdoor series impact test was carried out. The results show that an increase in the thickness of the cushion can effectively reduce the maximum impact force, and the peak acceleration increases with the thickness of the cushion, especially when the thickness of the buffer layer is 0.1 m and 0.2 m, the maximum value increases sharply. It can be obviously observed that there exists an exponential relation between the peak acceleration and the thickness of the cushion. According to the principle of dimensional analysis, the maximum impact depth of the cushion layer is directly proportional to the square of the kinetic energy, and the calculation formula is inversely proportional to the maximum incident impact force, respectively. The maximum impact depth of the cushion layer is also in good agreement with the actual measured value. The attenuation rate of the incident impact force in the cushion layer increases exponentially with the increase of the thickness of the cushion, and the peak impact force can be attenuated by about 70% under the thickness of the cushion layer of 0.6 m. With the increase of the cumulative impact energy level, the RC slab undergoes bending initiation and expansion, secondary bending cracks, shear cracks appearing, and further central bending cracks penetration, At the end of the test, the RC slab showed the typical bending failure characteristics.
[1] | SHRODER J F Jr, BISHOP M P. Mass movement in the Himalaya: new insights and research directions[J]. Geomorphology,1998,26(1/2/3):13 − 35. |
[2] | 郭江, 王全才, 张群利, 等. 落石冲击荷载下框架门式棚洞结构优化探讨[J]. 水文地质工程地质,2014,41(6):92 − 97. [GUO Jiang, WANG Quancai, ZHANG Qunli, et al. Exploration of structural optimization for the frame-type shed-tunnel under the impact of load of rock-fall[J]. Hydrogeology & Engineering Geology,2014,41(6):92 − 97. (in Chinese with English abstract) |
[3] | 胡卸文, 梅雪峰, 杨瀛, 等. 落石冲击荷载作用下的桩板拦石墙结构动力响应[J]. 工程地质学报,2019,27(1):123 − 133. [HU Xiewen, MEI Xuefeng, YANG Ying, et al. Dynamic response of pile-plate rock retaining wall under impact of rockfall[J]. Journal of Engineering Geology,2019,27(1):123 − 133. (in Chinese with English abstract) |
[4] | LUO H Y, COOPER W L, LU H B. Effects of particle size and moisture on the compressive behavior of dense Eglin sand under confinement at high strain rates[J]. International Journal of Impact Engineering,2014,65:40 − 55. doi: 10.1016/j.ijimpeng.2013.11.001 |
[5] | LI J C, MA G W. Experimental study of stress wave propagation across a filled rock joint[J]. International Journal of Rock Mechanics and Mining Sciences,2009,46(3):471 − 478. doi: 10.1016/j.ijrmms.2008.11.006 |
[6] | CALVETTI F, PRISCO C D, VECCHIOTTI M. Experimental and numerical study of rock-fall impacts on granular soils[J]. Rivista Italiana Di Geotecnica,2005,4(4). |
[7] | PRISCO C D, VECCHIOTTI M. Design charts for evaluating impact forces on dissipative granular soil cushions[J]. Journal of Geotechnical and Geoenvironmental Engineering,2010,136(11):1529 − 1541. doi: 10.1061/(ASCE)GT.1943-5606.0000363 |
[8] | 马炜. 散体介质冲击载荷作用下力学行为理论分析与算法实现[D]. 北京: 北京大学, 2008. MA Wei. Dynamical behavior of granular Materials under impact[D]. Beijing: Peking University, 2008. (in Chinese with English abstract) |
[9] | SEAMAN L. One-dimensional stress wave propagation in soils[R]. Defense Technical Information Center, 1966. |
[10] | 于潇, 陈力, 方秦. 珊瑚砂中应力波衰减规律的实验研究[J]. 岩石力学与工程学报,2018,37(6):1520 − 1529. [YU Xiao, CHEN Li, FANG Qin. Experimental study on the attenuation of stress wave in coral sand[J]. Chinese Journal of Rock Mechanics and Engineering,2018,37(6):1520 − 1529. (in Chinese with English abstract) |
[11] | 袁进科, 黄润秋, 裴向军. 滚石冲击力测试研究[J]. 岩土力学,2014,35(1):48 − 54. [YUAN Jinke, HUANG Runqiu, PEI Xiangjun. Test research on rockfall impact force[J]. Rock and Soil Mechanics,2014,35(1):48 − 54. (in Chinese with English abstract) |
[12] | 王星, 周天跃, 师江涛, 等. 基于自由落体的落石冲击土层的理论及LS-DYNA模拟研究[J]. 北京交通大学学报,2019,43(4):9 − 17. [WANG Xing, ZHOU Tianyue, SHI Jiangtao, et al. Theoretical and LS-DYNA simulation study of based on the theory of free-fall rockfall's impact on soil layer[J]. Journal of Beijing Jiaotong University,2019,43(4):9 − 17. (in Chinese with English abstract) doi: 10.11860/j.issn.1673-0291.20190015 |
[13] | RONCO C, OGGERI C, PEILA D. Design of reinforced ground embankments used for rockfall protection[J]. Natural Hazards and Earth System Sciences,2009,9(4):1189 − 1199. doi: 10.5194/nhess-9-1189-2009 |
[14] | 杨其新, 关宝树. 落石冲击力计算方法的试验研究[J]. 铁道学报, 1996, 18(1):101−106. YANG Qixin, GUAN Baoshu. Test and research on calculating method of falling stone impulsive force[J]. Journal of the China Railway Society, 1996, 18(1): 101 − 106. (in Chinese with English abstract) |
[15] | 叶四桥, 陈洪凯, 唐红梅. 落石冲击力计算方法的比较研究[J]. 水文地质工程地质,2010,37(2):59 − 64. [YE Siqiao, CHEN Hongkai, TANG Hongmei. Comparative research on impact force calculation methods for rockfalls[J]. Hydrogeology & Engineering Geology,2010,37(2):59 − 64. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-3665.2010.02.013 |
[16] | WANG B L, CAVERS D S. A simplified approach for rockfall ground penetration and impact stress calculations[J]. Landslides,2008,5(3):305 − 310. doi: 10.1007/s10346-008-0123-6 |
[17] | 中华人民共和国交通运输部. 公路路基设计规范: JTG D30—2015[S]. 北京: 人民交通出版社, 2015. Ministry of Transport of the People's Republic of China. Specifications for Design of Highway Subgrades: JTG D30—2015[S]. Beijing: China Communications Press, 2015. (in Chinese) |
[18] | MOUGIN J, PERROTIN P, MOMMESSIN M, et al. Rock fall impact on reinforced concrete slab: an experimental approach[J]. International Journal of Impact Engineering,2005,31(2):169 − 183. doi: 10.1016/j.ijimpeng.2003.11.005 |
[19] | DELHOMME F, MOMMESSIN M, MOUGIN J, et al. Simulation of a block impacting a reinforced concrete slab with a finite element model and a mass-spring system[J]. Engineering Structures,2007,29(11):2844 − 2852. doi: 10.1016/j.engstruct.2007.01.017 |
[20] | ZHAO P, XIE L Z, LI L P, et al. Large-scale rockfall impact experiments on a RC rock-shed with a newly proposed cushion layer composed of sand and EPE[J]. Engineering Structures,2018,175:386 − 398. doi: 10.1016/j.engstruct.2018.08.046 |
[21] | 袁博, 祝介旺. 滚石冲击下棚洞破坏动力响应分析及改进对策−以川藏公路(安久拉山南麓)门式棚洞为例[J]. 水文地质工程地质,2019,46(6):57 − 66. [YUAN Bo, ZHU Jiewang. Dynamic response analyses and improvement countermeasures of shed-tunnel destruction under rolling stone impact: a case study of the shed-tunnel in the southern foot of the Anjiula Mountain on the Sichuan-Tibet Highway[J]. Hydrogeology & Engineering Geology,2019,46(6):57 − 66. (in Chinese with English abstract) |
[22] | KAWAHARA S, MURO T. Effects of dry density and thickness of sandy soil on impact response due to rockfall[J]. Journal of Terramechanics,2006,43(3):329 − 340. doi: 10.1016/j.jterra.2005.05.009 |
[23] | LABIOUSE V, DESCOEUDRES F, MONTANI S. Experimental study of rock sheds impacted by rock blocks[J]. Structural Engineering International,1996,6(3):171 − 176. doi: 10.2749/101686696780495536 |
[24] | 中国人民共和国铁道部. 铁路隧道设计规范: TB 10003—2005[S]. 北京: 中国铁道出版社, 2005. Ministry of Railways of the People's Republic of China. Code for design on tunnel of railway: TB 10003—2005[S]. Beijing: China Railway Publishing House, 2005. (in Chinese) |
[25] | 叶四桥, 陈洪凯, 唐红梅. 落石冲击力计算方法[J]. 中国铁道科学,2010,31(6):56 − 62. [YE Siqiao, CHEN Hongkai, TANG Hongmei. The calculation method for the impact force of the rockfall[J]. China Railway Science,2010,31(6):56 − 62. (in Chinese with English abstract) |
[26] | 何思明, 沈均, 吴永. 滚石冲击荷载下棚洞结构动力响应[J]. 岩土力学,2011,32(3):781 − 788. [HE Seming M, SHEN Jun, WU Yong. Rock shed dynamic response to impact of rock-fall[J]. Rock and Soil Mechanics,2011,32(3):781 − 788. (in Chinese with English abstract) doi: 10.3969/j.issn.1000-7598.2011.03.024 |
[27] | 裴向军, 刘洋, 王东坡. 滚石冲击棚洞砂土垫层耗能缓冲机理研究[J]. 四川大学学报(工程科学版),2016,48(1):15 − 22. [PEI Xiangjun, LIU Yang, WANG Dongpo. Study on the energy dissipation of sandy soil cushions on the rock-shed under rockfall impact load[J]. Journal of Sichuan University (Engineering Science Edition),2016,48(1):15 − 22. (in Chinese with English abstract) |
Impact test set-up
Strain gauges (the number in parentheses is the bottom strain gauge)
Acceleration time history curve of the condition B2-0.1m-7m
Relationship between the peak acceleration and thickness of the cushion layer
Comparison of the tests and the calculations at different methods with those of the national standards and the other
Diffusion and distribution characteristics of the impact force
Transmission time history curve at different falling heights
Relationship between the cushion layer thickness and dimensionless impact force
Central deflection characteristics of RC slab
RC slab deflection and strain under C2-0.5m-7m
Relationship between the impact loading and displacement
Energy distribution ratio
RC slab failure process