软弱围岩隧道预衬砌法实施效果模型试验研究
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摘要
开展软弱围岩隧道预衬砌法大型三维地质力学室外坑内模型试验,对比分析常载和超载条件下设置预衬砌、不设置预衬砌预收敛变形、收敛变形、掌子面挤出位移、径向围岩压力及失稳破坏过程。结果表明:全风化V级花岗岩地质条件下铁路双线隧道采用预衬砌法,预收敛率减小20%～30%、拱顶沉降和水平收敛分别降低25%和80%、洞周径向围岩压力增大1.1倍;不设置预衬砌段开挖过程对超前核心土纵向影响范围约为0.7D(D为隧道跨度),设置预衬砌段影响范围缩小至0.3D、降幅近60%;超载条件下隧洞失稳过程为:边墙、拱顶、掌子面岩体"剥离–滑移–垮塌",最终形成深度分别为2,1.4,1.2m的塌穴;隧道稳定性判定参考极限位移值可取拱顶沉降157mm、水平收敛93mm、掌子面挤出位移225mm。研究成果为新意法理念下预衬砌全断面大型机械开挖提供一定的理论依据。
Preconvergent deformation,convergent deformation,face extrusion displacement,radial pressure of surrounding rock and failure process of instability are analyzed under the normal load and overload,a model test of large three-dimensional geomechanics outside the pit is carried out for the pre-lining method of tunnel in soft surrounding rock. The rate of preconvergence is reduced by 20%–30%,the settlement of the vault and the horizontal convergence can be reduced by 25% and 80%,the pressure of surrounding rock in the circumference of the hole is increased by 1.1 times while the pre-lining method is used in double line railway tunnel under the geological conditions of the fully weathered granite with grade V. The longitudinal influence range of the advanced core soil is about 0.3 D in condition A and 0.7 D in condition B,the decline is nearly 60%. The instability process of tunnel is peeling-slip-collapse of rock mass,and the collapse is finally formed with 2 m depth of side wall,1.4 m depth of vault,1.2 m depth of excavating face. Limit displacement value of stability criterion of tunnel is recommended 157 mm of vault settlement,93 mm of horizontal convergence and 225 mm of face extrusion displacement. The research results provide a certain theoretical basis for the full-face excavation of large machinery with pre-lining according to the basic theory of ADECO-RS.
Preconvergent deformation,convergent deformation,face extrusion displacement,radial pressure of surrounding rock and failure process of instability are analyzed under the normal load and overload,a model test of large three-dimensional geomechanics outside the pit is carried out for the pre-lining method of tunnel in soft surrounding rock. The rate of preconvergence is reduced by 20%–30%,the settlement of the vault and the horizontal convergence can be reduced by 25% and 80%,the pressure of surrounding rock in the circumference of the hole is increased by 1.1 times while the pre-lining method is used in double line railway tunnel under the geological conditions of the fully weathered granite with grade V. The longitudinal influence range of the advanced core soil is about 0.3 D in condition A and 0.7 D in condition B,the decline is nearly 60%. The instability process of tunnel is peeling-slip-collapse of rock mass,and the collapse is finally formed with 2 m depth of side wall,1.4 m depth of vault,1.2 m depth of excavating face. Limit displacement value of stability criterion of tunnel is recommended 157 mm of vault settlement,93 mm of horizontal convergence and 225 mm of face extrusion displacement. The research results provide a certain theoretical basis for the full-face excavation of large machinery with pre-lining according to the basic theory of ADECO-RS.
引文
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[13]王秀英,王藤,李孔明,等.预切槽法开挖隧道地层变形及预筑拱受力试验[J].中国公路学报,2017,30(7):101-109.(WANGXiuying,WANG Teng,LI Kongming,et al.Experiment on ground deformation during tunneling and pre-arch stress by pre-cutting method[J].China Journal of Highway and Transport,2017,30(7):101-109.(in Chinese))
[14]韩高升,王秀英,王北华.机械预切槽法施工过程中槽内混凝土相关问题研究[J].现代隧道技术,2017,54(1):9-16.(HAN Gaosheng,WAGN Xiuying,WANG Beihua.On some issues with concrete during tunneling by the mechanical pre-cutting method[J].Modern Tunnelling Technology,2017,54(1):9-16.(in Chinese))
[2]BOUGARD J F.Mechanical pre-cutting method[J].Tunnelling and Underground Space Technology,1988,3(2):163-167.
[3]王道远,袁金秀,李俊,等.考虑施工特性的浅埋软弱洞口段管棚变形量预测及工程应用[J].岩石力学与工程学报,2017,36(3):716-724.(WANG Daoyuan,YUAN Jinxiu,LI Jun,et al.Deformation prediction of pipe roof in shallow soft portal section of tunnel considering construction feature and its application[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(3):716-724.(in Chinese))
[4]陶龙光,侯公羽.超前锚杆预支护机理的力学模型研究[J].岩石力学与工程学报,1966,15(3):242-249.(TAO Longguang,HOUGongyu.Study on the mechanical model in pre-support mechanism of forepoling bolt[J].Chinese Journal of Rock Mechanics and Engineering,1966,15(3):242-249.(in Chinese))
[5]崔光耀,王道远,倪嵩陟,等.玄武岩纤维混凝土隧道衬砌承载特性模型试验研究[J].岩土工程学报,2017,39(2):311-318.(CUIGuangyao,WANG Daoyuan,NI Songzhi,et al.Model tests on bearing characteristics of basalt fiber-reinforced concrete tunnel linings[J].Chinese Journal of Geotechnical Engineering,2017,39(2):311-318.(in Chinese))
[6]崔光耀,王道远,倪嵩陟,等.软弱围岩隧道钢纤维混凝土衬砌承载特性模型试验研究[J].岩土工程学报,2017,39(10):1 807-1 813.(CUI Guangyao,WANG Daoyuan,NI Songzhi,et al.Model tests on bearing characteristics of steel fiber-reinforced concrete lining of weak surrounding rock tunnel[J].Chines Journal of Geotechnical Engineering,2017,39(10):1 807-1 813.(in Chinese))
[7]孙付峰,刘涛,雷刚.新意法在富水砂层的适用性研究[J].现代隧道技术,2014,51(1):171-178.(SUN Fufeng,LIU Tao,LEIGang.Research on the applicability of adeco-rs in a water-rich sand stratum[J].Modern Tunnelling Technology,2014,51(1):171-178.(in Chinese))
[8]刘钟,柳建国,张义,等.隧道全方位高压喷射注浆拱棚超前支护新技术[J].岩石力学与工程学报,2009,28(1):59-65.(LIUZhong,LIU Jianguo,ZHANG Yi,et al.New technique of rotary horizontal jet grouting for arched tunnel pre-support[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(1):59-65.(in Chinese))
[9]GERHARD S.Das Verfahren des mechanischen Voreinschneidens im Tunnelbau[J].Strassen und Tiefbau,1986,26(2):32-34.
[10]关宝树.隧道施工的技术特性、理念及其发展[J].铁道建筑技术,2003,(3):1-6.(GUAN Baoshu.Technical character,idea of tunnel construction and its development[J].Railway Construction Technology,2003,(3):1-6.(in Chinese))
[11]王秀英,张鍼,吕和林,等.机械预切槽法开挖软土隧道地层变形研究[J].岩土力学,2005,26(1):140-144.(WANG Xiuying,ZHANG Zhen,LU Helin,et.A study of ground deformation when excavating tunnel in soil by Mechanical pre-cutting method[J].Rock and Soil Mechanics,2005,26(1):140-144.(in Chinese))
[12]孙兵.预切槽法开挖黄土隧道预衬砌支护参数研究[J].铁道工程学报,2017,(9):77-82.(SUN Bing.Research on the parameters of pre-lining support in loess tunnel[J].Journal of Railway Engineering Society,2017,(9):77-82.(in Chinese))
[13]王秀英,王藤,李孔明,等.预切槽法开挖隧道地层变形及预筑拱受力试验[J].中国公路学报,2017,30(7):101-109.(WANGXiuying,WANG Teng,LI Kongming,et al.Experiment on ground deformation during tunneling and pre-arch stress by pre-cutting method[J].China Journal of Highway and Transport,2017,30(7):101-109.(in Chinese))
[14]韩高升,王秀英,王北华.机械预切槽法施工过程中槽内混凝土相关问题研究[J].现代隧道技术,2017,54(1):9-16.(HAN Gaosheng,WAGN Xiuying,WANG Beihua.On some issues with concrete during tunneling by the mechanical pre-cutting method[J].Modern Tunnelling Technology,2017,54(1):9-16.(in Chinese))