石质铁路隧道初期支护优化研究
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摘要
以蒙华铁路九岭山隧道为工程背景,运用强度折减法计算围岩强度储备并将其作为围岩稳定性的参考指标。依据现场监测,得到初期支护的受力特征。基于围岩强度储备指标与初期支护的受力特征,对初期支护进行优化设计,并应用于现场。研究结果表明:在围岩具有足够强度储备的前提下,初期支护主要承受形变压力;系统锚杆未发挥作用,喷射混凝土抗压性能未被充分利用,格栅钢架钢筋难以发挥其抗拉和抗弯性能;可将现有初期支护"喷射混凝土+格栅钢架+系统锚杆"的结构形式优化为"喷射混凝土+格栅钢架"。对原有设计和优化方案进行数值模拟,对比其锚杆轴力与喷射混凝土应力分布,同时应用现场试验验证该优化方案的安全性与可行性。该优化方案已在蒙华铁路应用推广。
This paper took the Jiulingshan tunnel of Menghua railway as the engineering background, the strength reserve of surrounding rock was used as a reference index for the stability of surrounding rock which was calculated by the strength reduction method. The stress characteristic of primary support was obtained according to the in-site monitoring. Based on the strength reserve of surrounding rock and the stress characteristic of primary support, the primary support was optimized and applied to the site. The results show that, under the premise that the surrounding rock has sufficient strength reserve, the primary support is mainly subjected to the pressure of deformation. The systemic anchor bolts do not play an role. The compressive properties of concrete are not fully utilized. The tensile and bending behavior of the rebar in steel frames is difficult to deform. The structure of the existing primary support "shotcrete + steel frames + systemic anchor bolts" can be optimized into "shotcrete + steel frames". The original design and optimized scheme are numerically simulated, and the axial force and the stress distribution of shotcrete are compared. At the same time, the safety and feasibility of the optimized scheme are verified by in-site test. Now it has been popularized and applied in Menghua railway.
This paper took the Jiulingshan tunnel of Menghua railway as the engineering background, the strength reserve of surrounding rock was used as a reference index for the stability of surrounding rock which was calculated by the strength reduction method. The stress characteristic of primary support was obtained according to the in-site monitoring. Based on the strength reserve of surrounding rock and the stress characteristic of primary support, the primary support was optimized and applied to the site. The results show that, under the premise that the surrounding rock has sufficient strength reserve, the primary support is mainly subjected to the pressure of deformation. The systemic anchor bolts do not play an role. The compressive properties of concrete are not fully utilized. The tensile and bending behavior of the rebar in steel frames is difficult to deform. The structure of the existing primary support "shotcrete + steel frames + systemic anchor bolts" can be optimized into "shotcrete + steel frames". The original design and optimized scheme are numerically simulated, and the axial force and the stress distribution of shotcrete are compared. At the same time, the safety and feasibility of the optimized scheme are verified by in-site test. Now it has been popularized and applied in Menghua railway.
引文
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[13]张顶立,陈峰宾,房倩.隧道初期支护结构受力特性及适用性研究[J].工程力学,2014,31(7):78-84.ZHANG Dingli,CHEN Fengbin,FANG Qian.Study on mechanical characteristics and applicability of primary lining used in tunnel[J].Engineering Mechanics,2014,31(7):78-84.
[14]邓斌,饶和根,廖卫平,等.软岩隧道支护结构优化研究[J].铁道科学与工程学报,2017,14(10):2203-2213.DENG Bin,RAO Hegen,LIAO Weiping,et al.Optimization of the soft rock tunnel support structure[J].Journal of Railway Science and Engineering,2017,14(10):2203-2213.
[15]郑颖人,赵尚毅.岩土工程极限分析有限元法及其应用[J].土木工程学报,2005,38(1):93-104.ZHENG Yingren,ZHAO Shangyi.Limit state finite element method for geotechnical engineering analysis and its applications[J].China Civil Engineering Journal,2005,38(1):93-104.
[16]Grimstad E,Barton N.Updating of the Q-system for NMT[C]//Proceedings of the International Symposium on Sprayed Concrete-Modern Use of Wet Mix Sprayed Concrete for Underground Support,Oslo:Fagernes,Norwegian Concrete Association,1993.
[17]张常光,曾开华.等值地应力下岩质圆形隧道位移释放系数比较及应用[J].岩石力学与工程学报,2015,34(3):498-510.ZHANG Changguang,ZENG Kaihua.Comparisons and applications of displacement release coefficients for a circular rock tunnel subjected to isotropic geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(3):498-510.
[2]Bieniawski Z T.Engineering classification of jointed rock masses[J].Civil Engineer in South Africa,1973,15:335-343.
[3]Celada B,Tardáguila I,Bieniawski Z T.Innovating tunnel design by an improved experience-based RMRsystem[C]//Proceedings of the World Tunnel Congress2014,Foz do Igua?u,2014.
[4]Barton N,Grimstad E,Aas G,et al.Norwegian method of tunnelling[J].World Tunnelling,1992,5(5):231-2,235-8.
[5]Hoek E,Brown E T.Practical estimates of rock mass strength[J].International Journal of Rock Mechanics&Mining Sciences,1997,34(8):1165-1186.
[6]Sonmez H,Ulusay R.Modifications to the geological strength index(GSI)and their applicability to stability of slopes[J].International Journal of Rock Mechanics&Mining Sciences,1999,36(6):743-760.
[7]TB 10003-2016,铁路隧道设计规范[S].TB 10003-2016,Code for design of railway tunnel[S].
[8]JTG D70-2004,公路隧道设计规范[S].JTG D70-2004,Code for design of road tunnel[S].
[9]CEN.EN 1997-1:2004 Eurocode 7:Geotechnical design-Part 1:General rules.Brussels:European Committee for Standardisation[S].
[10]谭忠盛,喻渝,王明年,等.大断面深埋黄土隧道锚杆作用效果的试验研究[J].岩石力学与工程学报,2008,27(8):1618-1625.TAN Zhongsheng,YU Yu,WANG Mingnian,et al.Experimental research on bolt anchorage effect on large-section deep-buried tunnel in loess[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(8):1618-1625.
[11]谭忠盛,喻渝,王明年,等.大断面浅埋黄土隧道锚杆作用效果的试验研究[J].岩土力学,2008,29(2):491-495.TAN Zhongsheng,YU Yu,WANG Mingnian,et al.Experimental study on bolt effect on large section shallow depth loess tunnels[J].Rock and Soil Mechanics,2008,29(2):491-495.
[12]陈建勋,杨善胜,罗彦斌,等.软弱围岩隧道取消系统锚杆的现场试验研究[J].岩土力学,2011,32(1):15-20.CHEN Jianxun,YANG Shansheng,LUO Yanbin,et al.Field test research on elimination of systematic rock bolts in weak rock tunnel[J].Rock and Soil Mechanics,2011,32(1):15-20.
[13]张顶立,陈峰宾,房倩.隧道初期支护结构受力特性及适用性研究[J].工程力学,2014,31(7):78-84.ZHANG Dingli,CHEN Fengbin,FANG Qian.Study on mechanical characteristics and applicability of primary lining used in tunnel[J].Engineering Mechanics,2014,31(7):78-84.
[14]邓斌,饶和根,廖卫平,等.软岩隧道支护结构优化研究[J].铁道科学与工程学报,2017,14(10):2203-2213.DENG Bin,RAO Hegen,LIAO Weiping,et al.Optimization of the soft rock tunnel support structure[J].Journal of Railway Science and Engineering,2017,14(10):2203-2213.
[15]郑颖人,赵尚毅.岩土工程极限分析有限元法及其应用[J].土木工程学报,2005,38(1):93-104.ZHENG Yingren,ZHAO Shangyi.Limit state finite element method for geotechnical engineering analysis and its applications[J].China Civil Engineering Journal,2005,38(1):93-104.
[16]Grimstad E,Barton N.Updating of the Q-system for NMT[C]//Proceedings of the International Symposium on Sprayed Concrete-Modern Use of Wet Mix Sprayed Concrete for Underground Support,Oslo:Fagernes,Norwegian Concrete Association,1993.
[17]张常光,曾开华.等值地应力下岩质圆形隧道位移释放系数比较及应用[J].岩石力学与工程学报,2015,34(3):498-510.ZHANG Changguang,ZENG Kaihua.Comparisons and applications of displacement release coefficients for a circular rock tunnel subjected to isotropic geostresses[J].Chinese Journal of Rock Mechanics and Engineering,2015,34(3):498-510.