西山坪近水平煤系地层隧道围岩稳定性研究
摘要
虽然岩石强度的大小对岩体的强度及安全稳定性起决定性作用，但在结构和构造面的影响下岩体的强度及安全稳定性受到极大的削弱。在许多情况下由于软弱岩层、结构与构造面的存在，因岩石强度不足引起的强度破坏或沿结构与构造面失稳破坏的情况时有发生。成为地下空间稳定性研究的重要关注方面。
沉积岩是陆地上分布最为广泛的岩石类型，也是我们在地下工程施工中经常遇到的围岩类型；在其成岩的过程中形成的各个层面、不同强度的软硬互层，与地质构造运动中形成的各种节理裂隙相互切割作用，对围岩的稳定性造成重要的影响。地下空间体与岩体结构、构造面的不同切割关系，与软硬岩层的不同空间位置，对围岩的稳定性会产生不同的影响，这其中又以近水平围岩的影响最为不利。
本文结合西山坪隧道的修建背景，以施工量测与监控的结果为基础，选择了有代表性断面，对单一巨厚围岩不同产状、穿煤系地层段、上伏及下伏采空回填区段的内空收敛情况进行了对比分析。在此基础上，利用2D-σ数值分析软件对初期支护后围岩应力重分布及喷层应力进行了数值分析。
研究结果表明：
① 围岩的倾角对内空收敛影响大，急倾斜岩层收敛稳定快于缓倾斜岩层。
② 岩层厚度在缓倾斜时对围岩稳定起控制作用，厚层硬岩整体稳定性好于薄层状硬岩。
③ 隧道围岩拱顶下沉的变化受含煤软岩层（采空回填区）与隧道的相对位置影响，在含煤软岩层（采空回填区）由隧道底部上升至拱顶的过程中，累计拱顶下沉值呈现出先升后降的规律，其中在拱基线附近引起的拱顶下沉值最大，墙基附近最小。
④ 数值分析显示，软硬岩层互层时，围岩应力分布在岩层层面附近变化较大，应力等值线发生折曲；喷层应力也在软岩层附近变大。
⑤ 采空回填区对曲墙喷层应力影响较大，尤其是对喷层的切向应力有由压应力向拉应力发展的趋势，有诱发纵向张裂隙的危险。
⑥ 对照现场实际，在近水平煤系地层中修建隧道，如有厚层硬岩层控制，只要对局部软岩层加强支护控制，是可以保证围岩的整体稳定的。
本文对近水平煤系地层中修筑隧道的围岩稳定性进行了深入分析，在含煤岩（采空回填区）的围岩变形及应力重分布规律的研究上有所创新，为近水平围岩的支护设计优化提供了可靠依据。丰富了新奥法设计施工在煤系地层中的理论与实践基础，对矿区修筑隧道的支护施工及稳定性研判具有指导作用。
Although the strength and the stability of rock mass are determined by rock strength, they are weakened more by the joints and fabric. Because of the weakened strata, joints and fabric, in many instances, breakage by lowered strength or unsteady along the joints and fabric is the antinational problem in underground space stability research.
In the Dissertation, base on the conclusions of measurements and field monitoring, choosing the representative sections from thick single layer with different angle of dip, coal-bearing strata and the backfilling over or under the tunnel, contrastively construe the space convergence, get the different characters about the speed and the cumulative convergence among them. Analyze the affections of surrounding rock deformation stability due to the layer angle and rock strength. Using the 2D-σ software, through the numerical analysis, it get the properties of stress redistribution in surrounding rock at the coal-bearing strata and the backfilling over or under the tunnel, also, the character of stress in shotcrete strata. These offer some references for security and economy in tunnel support design. At last, combining with space convergence of surround rock, numerical analysis conclusion and field support measurements, it gives a security and stability appraisal of flat dip layer in Xi Shanping Tunnel; also, some advices are given about the monitorial work and numerical simulation.
The research results show that:
1. The angle of dip give more affection on space convergence, the steep dip layer are stable fast than the flat dip layer.
2. In flat dip layer, the seam thickness control the stability of the wall rock, the thick-bedded hard rock is stable than the thin-bedded hard rock.
3. The arch apex subsidence is varied by the relationship between the tunnel and the coal-bearing strata (or the backfilling). As the coal-bearing strata rising from the bottom of tunnel to the top, the arch apex subsidence, at first, rise to its top, then turn to drop a little.
4. According to the numerical analysis conclusion, the stress change quickly at the bedding surface between the hard rock and soft rock so does
the shotcrete stress.
5. Affected by the backfilling, the tangential stress of shotcrete has a tendency is for pressure stress to be tensile stress; it is dangerous to induce the axial cranny.
6. As the field work in Xi Shanping Tunnel showing, constructing tunnel in flat dip coal-bearing strata, if there is thick-bedded hard rock nearby, the stability of the wall rock is ensured by the control in soft rock supporting reinforce.
These results offer some reference to design and construct by NATM in coal strata regions, which enlarge the knowledge of wall rock stability both in theory and practice, too.
沉积岩是陆地上分布最为广泛的岩石类型，也是我们在地下工程施工中经常遇到的围岩类型；在其成岩的过程中形成的各个层面、不同强度的软硬互层，与地质构造运动中形成的各种节理裂隙相互切割作用，对围岩的稳定性造成重要的影响。地下空间体与岩体结构、构造面的不同切割关系，与软硬岩层的不同空间位置，对围岩的稳定性会产生不同的影响，这其中又以近水平围岩的影响最为不利。
本文结合西山坪隧道的修建背景，以施工量测与监控的结果为基础，选择了有代表性断面，对单一巨厚围岩不同产状、穿煤系地层段、上伏及下伏采空回填区段的内空收敛情况进行了对比分析。在此基础上，利用2D-σ数值分析软件对初期支护后围岩应力重分布及喷层应力进行了数值分析。
研究结果表明：
① 围岩的倾角对内空收敛影响大，急倾斜岩层收敛稳定快于缓倾斜岩层。
② 岩层厚度在缓倾斜时对围岩稳定起控制作用，厚层硬岩整体稳定性好于薄层状硬岩。
③ 隧道围岩拱顶下沉的变化受含煤软岩层（采空回填区）与隧道的相对位置影响，在含煤软岩层（采空回填区）由隧道底部上升至拱顶的过程中，累计拱顶下沉值呈现出先升后降的规律，其中在拱基线附近引起的拱顶下沉值最大，墙基附近最小。
④ 数值分析显示，软硬岩层互层时，围岩应力分布在岩层层面附近变化较大，应力等值线发生折曲；喷层应力也在软岩层附近变大。
⑤ 采空回填区对曲墙喷层应力影响较大，尤其是对喷层的切向应力有由压应力向拉应力发展的趋势，有诱发纵向张裂隙的危险。
⑥ 对照现场实际，在近水平煤系地层中修建隧道，如有厚层硬岩层控制，只要对局部软岩层加强支护控制，是可以保证围岩的整体稳定的。
本文对近水平煤系地层中修筑隧道的围岩稳定性进行了深入分析，在含煤岩（采空回填区）的围岩变形及应力重分布规律的研究上有所创新，为近水平围岩的支护设计优化提供了可靠依据。丰富了新奥法设计施工在煤系地层中的理论与实践基础，对矿区修筑隧道的支护施工及稳定性研判具有指导作用。
Although the strength and the stability of rock mass are determined by rock strength, they are weakened more by the joints and fabric. Because of the weakened strata, joints and fabric, in many instances, breakage by lowered strength or unsteady along the joints and fabric is the antinational problem in underground space stability research.
In the Dissertation, base on the conclusions of measurements and field monitoring, choosing the representative sections from thick single layer with different angle of dip, coal-bearing strata and the backfilling over or under the tunnel, contrastively construe the space convergence, get the different characters about the speed and the cumulative convergence among them. Analyze the affections of surrounding rock deformation stability due to the layer angle and rock strength. Using the 2D-σ software, through the numerical analysis, it get the properties of stress redistribution in surrounding rock at the coal-bearing strata and the backfilling over or under the tunnel, also, the character of stress in shotcrete strata. These offer some references for security and economy in tunnel support design. At last, combining with space convergence of surround rock, numerical analysis conclusion and field support measurements, it gives a security and stability appraisal of flat dip layer in Xi Shanping Tunnel; also, some advices are given about the monitorial work and numerical simulation.
The research results show that:
1. The angle of dip give more affection on space convergence, the steep dip layer are stable fast than the flat dip layer.
2. In flat dip layer, the seam thickness control the stability of the wall rock, the thick-bedded hard rock is stable than the thin-bedded hard rock.
3. The arch apex subsidence is varied by the relationship between the tunnel and the coal-bearing strata (or the backfilling). As the coal-bearing strata rising from the bottom of tunnel to the top, the arch apex subsidence, at first, rise to its top, then turn to drop a little.
4. According to the numerical analysis conclusion, the stress change quickly at the bedding surface between the hard rock and soft rock so does
the shotcrete stress.
5. Affected by the backfilling, the tangential stress of shotcrete has a tendency is for pressure stress to be tensile stress; it is dangerous to induce the axial cranny.
6. As the field work in Xi Shanping Tunnel showing, constructing tunnel in flat dip coal-bearing strata, if there is thick-bedded hard rock nearby, the stability of the wall rock is ensured by the control in soft rock supporting reinforce.
These results offer some reference to design and construct by NATM in coal strata regions, which enlarge the knowledge of wall rock stability both in theory and practice, too.
引文
[1] 杨明举，黎立新，王宏元，瑞士及北欧公路隧道建设技术，公路，2002，Volume: 2.119
[2] 杨屹东，德国公路隧道的设计、施工与管理，中外公路，2001，Volume: 21（5）.33
[3] 挪威隧道施工法，隧道译丛，1993，Volume: 7
[4] 刘伟，21世纪初我国公路隧道的关键技术，公路，2000，Volume: 11
[5] Williams, I.; Osborne, N.; Thai, Aw Eng. Recent Large-Diameter Tunnel Construction in Singapore Using Sprayed Concrete Linnings. Tunneling and Underground Space Technology. Volume: 14, Issue: 4, October - December, 1999, pp. 527-538
[6] Vera, A. V.; Gonzalez, G. M.; Gonzalez, L. B. R.; Gomez, A. S.; Vara, J. M. M. Twenty-Five Years of Subway Construction in Mexico City. Tunneling and Underground Space Technology Volume: 10, Issue: 1, January, 1995, pp. 65-77
[7] Ko?kar, M.K.; Akgün, H. Methodology for tunnel and portal support design in mixed limestone, schist and phyllite conditions: a case study in Turkey. International Journal of Rock Mechanics and Mining Sciences Volume: 40, Issue: 2, February, 2003, pp. 173-196
[8] 王焕文，王继良，锚喷支护，煤炭工业出版社，北京，1989
[9] 王守仁，应用新奥法的几个问题，铁道工程学报，1997，Volume: 1.105-111
[10] 郑志强，新奥法应用领域的拓展，科技情报开发与经济，1999，Volume: 3.40-42
[11] Ernest E.Wahlstrom. Tunneling in Rock. pp.57-62
[12] Brox, D.; Hagedorn, H. Extreme Deformation and Damage during the Construction of Large Tunnels，Tunneling and Underground Space Technology，Volume: 14, Issue: 1, January 3, 1999, pp. 23-28
[13] Okada, M.; Hamazuka, Y.; Okano, S，Field measurement controlling method of CD-NATM in urban tunnel，International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. Volume: 32, Issue: 3, April, 1995, pp. 123A
[14] Kovári, Kalman. History of the sprayed concrete lining method-part II: milestones up to the 1960s. Tunneling and Underground Space Technology. Volume: 18, Issue: 1, February, 2003, pp. 71-83
[15] Lackner, R.; Mang, H.A. Cracking in shotcrete tunnel shells. Engineering Fracture Mechanics Volume: 70, Issue: 7-8, May, 2003, pp. 1047-1068
[16] Jeng, F.-S.; Huang, T.-H. The holding mechanism of under-reamed rockbolts in soft rock. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts Volume: 36, Issue: 6, September, 1999, pp. 761-775
[17] Nomikos, P.P.; Sofianos, A.I.; Tsoutrelis, C.E. Symmetric wedge in the roof of a tunnel excavated in an inclined stress field. International Journal of Rock Mechanics and Mining Sciences Volume: 39, Issue: 1, January, 2002, pp. 59-67
[18] 于学馥.郑颖人.刘怀恒.方正昌.地下工程围岩稳定分析.第一版.北京.煤炭工业出版社.1983.
[19] 王思敬.杨志法等.地下工程岩体稳定性分析.第一版.北京.科学出版社.1984
[20] 李世辉.隧道围岩稳定分析与科学方法论问题.岩石力学与工程学报. Volume: 7. Issue: 1.1998.284-289
[21] Palmstr?m, Arild. Characterizing Rock Masses by the RMi for Use in Practical Rock Engineering, Part 2: Some practical applications of the Rock Mass index (RMi). Tunneling and Underground Space Technology. olume: 11, Issue: 3, July, 1996, pp. 287-303
[22] 日本、美国和欧洲开挖技术发展对比，隧道译丛，1993，Volume: 7.17-29
[23] 徐胜一.2D-σ程序及其在隧道工程中的应用.岩石力学与工程学报. 1988. Volume: 17. Issue:4. 475-477
[24] 靳晓光，李晓红，亢会明，线性——非线性GM模型在地下工程围岩变形模拟预报中的作用，公路隧道，Volume:
[25] 王芝银.杨志法等.岩石力学位移反演回顾及进展.西安矿业学院学报. 1988. Volume: 8. Issue:3. 1-10
[26] 郑颖人.董云飞等.地下工程锚喷支护设计指南.第一版.北京.中国铁道出版社.1988
[27] 李世辉. 隧道围岩稳定典型类比分析法.土木工程学报. 1992.Volume: 25. Issue:6. 73-75
[28] 陆士良.姜耀东.支护阻力对软岩巷道围岩的控制作用.岩土力学. 1998. Vol:19. Issue:1. 1-6
[29] 席道瑛.陈林.张涛.砂岩变形的各向异性. 岩石力学与工程学报. 1995. Vol:14. Issue:1. 49-58
[30] 张勤.陈志坚.朱代洪.陈松.层状裂隙岩体稳定性分析的主要问题.岩土工程学报. 2001.Vol:23. Issue:6. 753-756
[31] 王国民.软质粉砂岩变形与强度的试验分析.岩土力学. 2000.Vol:21. Issue:4. 340-342
[32] 重庆江北地质工程勘察院.国道212线重庆至合川高速公路缙云山西山坪隧道工程地质详细勘察报告
[33] 王渭明.时序分析在软岩巷道中的应用.煤炭科学技术. 1996. Vol:24. Issue:4. 39-43
[34] 张玉祥.岩土工程时间序列预报问题初探.岩石力学与工程学报. 1998. Vol:17. Issue:5. 552-558
[35] 李晓红.靳晓光.亢会明.顾义磊.杨新桦.西山坪隧道初期支护条件下围岩变形特征研究.西部探矿工程. 2001.Vol:13. Issue:2. 69-71
[36] 滕智明.朱金铨.混凝土结构及砌体结构.第一版.北京.中国建筑工业出版社.1992.14
[37] 亢会明.李晓红.靳晓光.顾义磊.李秀清.华蓥山隧道穿煤段施工技术.煤炭科学技术. V2001.ol:29. Issue:2. 10-11
[2] 杨屹东，德国公路隧道的设计、施工与管理，中外公路，2001，Volume: 21（5）.33
[3] 挪威隧道施工法，隧道译丛，1993，Volume: 7
[4] 刘伟，21世纪初我国公路隧道的关键技术，公路，2000，Volume: 11
[5] Williams, I.; Osborne, N.; Thai, Aw Eng. Recent Large-Diameter Tunnel Construction in Singapore Using Sprayed Concrete Linnings. Tunneling and Underground Space Technology. Volume: 14, Issue: 4, October - December, 1999, pp. 527-538
[6] Vera, A. V.; Gonzalez, G. M.; Gonzalez, L. B. R.; Gomez, A. S.; Vara, J. M. M. Twenty-Five Years of Subway Construction in Mexico City. Tunneling and Underground Space Technology Volume: 10, Issue: 1, January, 1995, pp. 65-77
[7] Ko?kar, M.K.; Akgün, H. Methodology for tunnel and portal support design in mixed limestone, schist and phyllite conditions: a case study in Turkey. International Journal of Rock Mechanics and Mining Sciences Volume: 40, Issue: 2, February, 2003, pp. 173-196
[8] 王焕文，王继良，锚喷支护，煤炭工业出版社，北京，1989
[9] 王守仁，应用新奥法的几个问题，铁道工程学报，1997，Volume: 1.105-111
[10] 郑志强，新奥法应用领域的拓展，科技情报开发与经济，1999，Volume: 3.40-42
[11] Ernest E.Wahlstrom. Tunneling in Rock. pp.57-62
[12] Brox, D.; Hagedorn, H. Extreme Deformation and Damage during the Construction of Large Tunnels，Tunneling and Underground Space Technology，Volume: 14, Issue: 1, January 3, 1999, pp. 23-28
[13] Okada, M.; Hamazuka, Y.; Okano, S，Field measurement controlling method of CD-NATM in urban tunnel，International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. Volume: 32, Issue: 3, April, 1995, pp. 123A
[14] Kovári, Kalman. History of the sprayed concrete lining method-part II: milestones up to the 1960s. Tunneling and Underground Space Technology. Volume: 18, Issue: 1, February, 2003, pp. 71-83
[15] Lackner, R.; Mang, H.A. Cracking in shotcrete tunnel shells. Engineering Fracture Mechanics Volume: 70, Issue: 7-8, May, 2003, pp. 1047-1068
[16] Jeng, F.-S.; Huang, T.-H. The holding mechanism of under-reamed rockbolts in soft rock. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts Volume: 36, Issue: 6, September, 1999, pp. 761-775
[17] Nomikos, P.P.; Sofianos, A.I.; Tsoutrelis, C.E. Symmetric wedge in the roof of a tunnel excavated in an inclined stress field. International Journal of Rock Mechanics and Mining Sciences Volume: 39, Issue: 1, January, 2002, pp. 59-67
[18] 于学馥.郑颖人.刘怀恒.方正昌.地下工程围岩稳定分析.第一版.北京.煤炭工业出版社.1983.
[19] 王思敬.杨志法等.地下工程岩体稳定性分析.第一版.北京.科学出版社.1984
[20] 李世辉.隧道围岩稳定分析与科学方法论问题.岩石力学与工程学报. Volume: 7. Issue: 1.1998.284-289
[21] Palmstr?m, Arild. Characterizing Rock Masses by the RMi for Use in Practical Rock Engineering, Part 2: Some practical applications of the Rock Mass index (RMi). Tunneling and Underground Space Technology. olume: 11, Issue: 3, July, 1996, pp. 287-303
[22] 日本、美国和欧洲开挖技术发展对比，隧道译丛，1993，Volume: 7.17-29
[23] 徐胜一.2D-σ程序及其在隧道工程中的应用.岩石力学与工程学报. 1988. Volume: 17. Issue:4. 475-477
[24] 靳晓光，李晓红，亢会明，线性——非线性GM模型在地下工程围岩变形模拟预报中的作用，公路隧道，Volume:
[25] 王芝银.杨志法等.岩石力学位移反演回顾及进展.西安矿业学院学报. 1988. Volume: 8. Issue:3. 1-10
[26] 郑颖人.董云飞等.地下工程锚喷支护设计指南.第一版.北京.中国铁道出版社.1988
[27] 李世辉. 隧道围岩稳定典型类比分析法.土木工程学报. 1992.Volume: 25. Issue:6. 73-75
[28] 陆士良.姜耀东.支护阻力对软岩巷道围岩的控制作用.岩土力学. 1998. Vol:19. Issue:1. 1-6
[29] 席道瑛.陈林.张涛.砂岩变形的各向异性. 岩石力学与工程学报. 1995. Vol:14. Issue:1. 49-58
[30] 张勤.陈志坚.朱代洪.陈松.层状裂隙岩体稳定性分析的主要问题.岩土工程学报. 2001.Vol:23. Issue:6. 753-756
[31] 王国民.软质粉砂岩变形与强度的试验分析.岩土力学. 2000.Vol:21. Issue:4. 340-342
[32] 重庆江北地质工程勘察院.国道212线重庆至合川高速公路缙云山西山坪隧道工程地质详细勘察报告
[33] 王渭明.时序分析在软岩巷道中的应用.煤炭科学技术. 1996. Vol:24. Issue:4. 39-43
[34] 张玉祥.岩土工程时间序列预报问题初探.岩石力学与工程学报. 1998. Vol:17. Issue:5. 552-558
[35] 李晓红.靳晓光.亢会明.顾义磊.杨新桦.西山坪隧道初期支护条件下围岩变形特征研究.西部探矿工程. 2001.Vol:13. Issue:2. 69-71
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