Geostress Field Analysis of Futang Tunnel, before and after Wenchuan Ms8.0 Earthquake
-
摘要: "5·12"汶川地震后，发震断裂上盘的高地应力本应获得一定程度的释放，但位于该地区的福堂隧道仍出现了较强烈岩爆灾害和饼裂岩芯等高应力特征.为研究该特殊高地应力现象，基于实测地应力值和地震前后区域地应力反演分析，获得了该特殊高应力现象的形成原因.结果表明："特殊高地应力"主要受断裂带逆冲推覆持续作用、浅表生改造、介质差异及其距发震断裂的距离效应等因素影响而综合形成；强震后福堂隧道靠映秀侧洞段应力有较大降幅，而靠汶川侧洞段应力值降幅较小且仍处于高应力状态；隧道K18+850~K21+450段最大地应力介于20~25 MPa之间.特殊的地应力特征使得隧道两端具有完全不同的工程特性，对不同应力值洞段的支护参数选取、施工方法及隧道造价等都具有重要的工程意义.Abstract: After an earthquake, such as the "5.12 Wenchuan earthquake", some of the high stresses in the hanging wall of seismic faults should be released. However, the rock mass surrounding the Futang Tunnel, is still under high stress, even after the earthquake, as evidenced by rockburst and core cracking. To investigate this issue, in-situ stress tests and back analysis of the tunnel's regional stress field, before and after the earthquake, were conducted to deduce the formation mechanism of this high stress. Research shows that the high stresses are produced by the integration of the continuous effects of fault thrusts, epigenetic and superficial reformation, medium differences, the effect of distance to the fault, and so on. The stress on the Yingxiu side of the Futang Tunnel decreased significantly after the earthquake, but on the Wenchuan side, there was little decline, and so the stress is still high. The maximum stress in Section K18+850-K21+450 is between 20-25 MPa. This unique stress distribution means that both sides of the tunnel require different engineering features, and have important engineering consequences for the design of support parameters, the construction method and the construction cost in different tunnel sections.
-
Key words:
- Wenchuan earthquake /
- high stress phenomenon /
- rockburst /
- initial stress field /
- distance effect
-
图 4 垂直方向模型边界条件
Figure 4. The boundary conditions of the model in the vertical direction
图 5 水平方向模型边界条件
Figure 5. The boundary conditions of the model in the horizontal direction
图 6 强震前后最大主应力曲线(负值为压应力, 下同)
Figure 6. Maximum principal stress curves before and after the earthquake (negative values mean compressive stress, the same below)
图 7 强震前后最小主应力曲线
Figure 7. Minimum principal stress curves before and after the earthquake
图 8 震前K19+940剖面最大主应力云图
Figure 8. Maximum principal stress cloud at section K19+940 before the earthquake
图 9 震后K19+940剖面最大主应力云图
Figure 9. Maximum principal stress cloud at section K19+940 after the earthquake
表 1 实测地应力与模拟计算结果表
Table 1. In-situ stress testing and the model calculation results
MPa 时间 测试位置 实测地应力结果 转换坐标后的结果 模拟计算结果 σ1 σ2 σ3 Sxx Syy Szz Sxx Syy Szz 震前 岷江左岸福堂电站地下厂房, 测点埋深235 m 18.4 16.5 11.3 28.65 14.36 16.18 28.4 11.4 19.23 岷江左岸太平驿引水隧洞2#施工平洞, 测点埋深200 m 31.3 17.5 10.4 16.10 17.59 12.51 19.2 18.2 12.6 震后 都汶高速公路福堂隧道K19+940, 测点埋深432 m 20.8 12.5 7.0 9.58 15.51 15.21 10.3 15.7 14.5 说明:σ1为最大主应力; σ2为中间主应力; σ3为最小主应力, Sxx、Syy、Szz为计算坐标应力. 
下载: 导出CSV
表 2 福堂隧道地应力测试结果
Table 2. The stress test results in the Futang tunnel
应力 量值/MPa 方向/(°) 倾角/(°) σ1 20.8 N34E 41.1 σ2 12.5 N10W -39.7 σ3 7.0 N79W 23.6
下载: 导出CSV
表 3 计算模型岩体力学参数
Table 3. The mechanical parameters of the rock mass for the numerical model
地层 重度/(MN·m-3) 体积模量/GPa 剪切模量/GPa 摩擦角/(°) 黏聚力/MPa 抗拉强度/MPa 强风化 0.020 0.7 3 32 0.2 0.1 弱风化 0.022 21.0 12 42 10.0 1.2 新鲜岩体 0.026 45.0 30 48 13.0 2.2
下载: 导出CSV
-
徐正, 李天斌, 孟陆波, 等.鹧鸪山隧道地应力反演模型及三维地应力[J].成都理工大学学报:自然科学版, 2014, 41(2):243-250. http://www.cqvip.com/QK/91405B/201402/49337239.htmlXU Zheng, LI Tianbing, MENG Lubo, et al. Zhegu Mountain tunnel ground stress inversion model and three dimensional ground stress[J]. Journal of Chengdu University of Technology:Science & Technology Edition, 2014, 41(2):243-250. http://www.cqvip.com/QK/91405B/201402/49337239.html 李四光.论地震[M].北京:地质出版社, 1977:11-12. 丰成君, 陈群策, 谭成轩, 等.汶川Ms8.0地震对龙门山断裂带附近地应力环境影响初探:以北川、江油地区为例[J].地震学报, 2013, 35(2):137-150. doi: 10.3969/j.issn.0253-3782.2013.02.001FENG Chengjun, Chen Qunce, TAN Chengxuan, et al.A preliminary study of the influence of Wenchuan Ms8.0 earthquake on in-situ stress state near Longmenshan fault zone[J]. Acta Seismologica Sinica, 2013, 35(2):137-150. doi: 10.3969/j.issn.0253-3782.2013.02.001 郭啟良, 王成虎, 马洪生, 等.汶川Ms8.0级大震前后的水压致裂原地应力测量[J].地球物理学报, 2009, 52(5):1395-1401. doi: 10.3969/j.issn.0001-5733.2009.05.029GUO Qiliang, WANG Chenghu, MA Hongsheng, et al. In-situ hudro-fracture stress measurement before and after the Wenchuan Ms8.0 earthquake of China[J]. Chinese Journal of Geophysics, 2009, 52(5):1395-1401. doi: 10.3969/j.issn.0001-5733.2009.05.029 李方全, 王连捷.华北地区地应力测量[J].地球物理学报, 1979, 22(1):1-8. doi: 10.3321/j.issn:0001-5733.1979.01.001LI Fangquan, WANG Lianjie. Stress measurements in north China[J]. Acta Seismologica Sinica, 1979, 22(1):1-8. doi: 10.3321/j.issn:0001-5733.1979.01.001 李方全, 孙世宗, 李立球.华北及郯庐断裂带地应力测量[J].岩石力学与工程学报, 1982, 1(1):74-86. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=CAS201303040000306764LI Fangquan, SUN Shizong, LI Liqiu. In-situ stress measurements in north China and Tancheng-Lujiang fault zone[J]. Chinese Journal of Rock Mechanics and Engineering, 1982, 1(1):74-86. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=CAS201303040000306764 李方全, 刘光勋.地应力测量、地壳上部应力状态与地震[J].中国地震, 1986, 2(1):50-55. doi: 10.1249-MSS.0b013e3181da4339/LI Fangquan, LIU Guangxun. Stress measurement, stressstateof uppercrust and earthquake research[J]. Earthquake Research in China, 1986, 2(1):50-55. doi: 10.1249-MSS.0b013e3181da4339/ 丰成君, 陈群策, 谭成轩, 等.龙门山断裂带东北段现今地应力环境研究[J].地球物理学进展, 2013, 28(3):1109-1121. http://d.old.wanfangdata.com.cn/Periodical/dqwlxjz201303002FENG Chengjun, CHEN Qunce, TAN Chenxuan, et al. Analysis on current in-situ stress state in northern segment of Longmenshan fault belt[J]. Progress in Geophysics, 2013, 28(3):1109-1121. http://d.old.wanfangdata.com.cn/Periodical/dqwlxjz201303002 秦向辉, 陈群策, 谭成轩, 等.龙门山断裂带西南段现今地应力状态与地震危险性分析[J].岩石力学与工程学报, 2013, 32(增刊1):2870-2876. http://d.old.wanfangdata.com.cn/Periodical/yslxygcxb2013z1038QIN Xianghui, CHEN Qunce, TAN Chengxun, et al. Analysis of current geostress state and seismic risk in southwest segment of Longmenshan fracture belt[J]. Chinese Journal of Rock Mechanics and Engineering, 2013, 32(Sup.1):2870-2876. http://d.old.wanfangdata.com.cn/Periodical/yslxygcxb2013z1038 蔡美峰, 乔兰, 李华斌.地应力测量原理和技术[M].北京:科学出版社, 1995:28-210. 景锋, 盛谦, 张勇慧, 等.我国原位地应力测量与地应力场分析研究进展[J].岩土力学, 2011, 32(2):51-58. http://d.old.wanfangdata.com.cn/Conference/7528628JING Feng, SHENG Qian, ZHANG Yonghui, et al. Study advance on in-site geostress measurement and analysis of initial geostress field in China[J]. Rock and Soil Mechanics, 2011, 32(2):51-58. http://d.old.wanfangdata.com.cn/Conference/7528628 王金安, 李飞.复杂地应力场反演优化算法及研究新进展[J].中国矿业大学学报, 2015, 44(2):189-205. http://d.old.wanfangdata.com.cn/Periodical/zgkydxxb201502001WANG Jinan, LI Fei. Review of inverse optimal algorithm of in-situ stress field and new achievement[J]. Journal of China University of Mining & Technology, 2015, 44(2):189-205. http://d.old.wanfangdata.com.cn/Periodical/zgkydxxb201502001 郑兵, 苏琴, 向平, 等.巴塘6.7级地震和雅江6.0级地震前后三叉口地区重力场变化情况[J].四川地震, 2006, 2(6):36-39. http://d.old.wanfangdata.com.cn/Periodical/scdz200602008ZHENG Bing, SUN Qin, XIANG Ping, et al. Gravity field changes compared before and after the M6.7 Batang and the M6.0 Yajiang earthquake around Shimian area[J]. Earthquake Research in Sichuan, 2006, 2(6):36-39. http://d.old.wanfangdata.com.cn/Periodical/scdz200602008 WAN Yongge, SHEN Zhengkang. Static Coulomb stress changes on faults caused by the 2008 Mw 7.9 Wenchuan, China earthquake[J]. Tectongophysics, 2010, 491:105-108. doi: 10.1016/j.tecto.2010.03.017 LUO Gang, LIU Mian. Stress evolution and fault interactions before and after the 2008 Great Wenchuan earthquake[J]. Techtonophysics, 2010, 491:127-140. doi: 10.1016/j.tecto.2009.12.019 LIAO C T, ZHANG C S, WU M L, et al. Stress change near the Kunlun fault before and after the Ms 8.1 Kunlun earthquake[J]. Geophys Reslett, 2010, 30(20):2027-2030. doi: 10.1029/2003GL018106/full TANAKA Y. OKA Y. Generation mechanism of rock bursts and water induced earthquakes under the tectonic stress field[J]. Rock Mechanics in Japan, 1979, 3(2):183-191. 王兰生, 李天斌, 徐进, 等.二郎山公路隧道岩爆及岩爆烈度分级[J].公路, 1991, 2:42-45. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199901174490WANG Lansheng, LI Tianbin, XU Jin, et al. Rock burst and rockburst intensity classification of Erlang Mountain highway tunnel[J]. Highway, 1991, 2:42-45. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=QK199901174490 周德培, 洪开荣.太平驿隧洞岩爆特征及防治措施[J].岩石力学与工程学报, 1995(2):171-178. doi: 10.3321/j.issn:1000-6915.1995.02.011ZHOU Depei, HONG Kairong. The rockburst features of Taipingyi tunnel and the prevention methods[J]. Chinese Journal of Rock Mechanics and Enigineering, 1995(2):171-178. doi: 10.3321/j.issn:1000-6915.1995.02.011 陈卫东.太平驿水电站工程勘察综述[R].成都: 中国水电顾问集团成都勘测设计研究院, 2006. 陈见行, 王洪林, 王晓卿.利用套孔应力解除法测量矿山原岩应力[J].山西焦煤科技, 2010, 34(2):31-33. doi: 10.3969/j.issn.1672-0652.2010.02.010CHEN Jianhang, WANG Hongling, WANG Xiaoqing. By making ues of borehole overcoring relieving method survey original rock stress of mine[J]. Shanxi Coking Coal Science & Technology, 2010, 34(2):31-33. doi: 10.3969/j.issn.1672-0652.2010.02.010 -
下载:
点击查看大图
图(10) / 表(3)
计量
- 文章访问数: 427
- HTML全文浏览量: 169
- PDF下载量: 133
- 被引次数: 0