학술논문
基于正交试验的大直径盾构下穿高铁桥梁的加固措施优化设计 / Optimization design of reinforcement measures for high-speed railway bridges with large diameter shield tunneling based on orthogonal test
Document Type
Academic Journal
Author
Source
中南大学学报（自然科学版） / Journal of Central South University（Science and Technology). 54(11):4481-4492
Subject
Language
Chinese
ISSN
1672-7207
Abstract
结合苏州桐泾路北延工程,建立大直径盾构下穿32 m简支箱梁施工全过程的有限元模型.通过现场实测数据与数值计算结果对比初步验证有限元模型的有效性.分别选取隔离桩桩长、桩径、桩隧净距或MJS法加固区域长度、宽度、高度等因素进行正交试验,引入墩顶变形抑制系数作为加固效果评价指标,经方差分析与显著性检验判别各因素对加固效果的影响程度,最后对土层加固关键设计参数进行优化.研究结果表明:仅采用隔离桩及纵横梁加固时,桩长是影响加固效果的敏感因素,优化桩长宜取为隧道底部埋深的1.29倍,沉降及纵向位移抑制系数分别为0.856和0.843.仅采用MJS法加固时,加固区域长度是影响加固效果的敏感因素,优化加固长度宜取为承台宽度的6.11倍,沉降及纵向位移抑制系数分别为0.748和0.787;当采用单一措施进行土层加固时,宜优先采用隔离桩及纵横梁加固;当采用隔离桩及纵横梁和MJS法联合加固时,优化桩长仍取为隧道底部埋深的1.29倍,优化加固长度宜取为承台宽度的4.56倍,沉降及纵向位移抑制系数分别为0.947和0.950,可满足桥上高铁列车正常运营的墩顶变形控制要求.研究成果可为开展大直径盾构下穿高铁桥梁影响区段合理土层加固设计提供参考.
Combined with the Tongjing Road North Extension Project in Suzhou,a finite element model of the whole construction process of 32 m simply supported box girder under a large-diameter shield was established.The effectiveness of the finite element model was preliminarily verified by comparing the field measured results with the numerical calculation results.Respectively isolated pile length,pile diameter,pile-tunnel clearance or MJS method strengthening regional factors such as length,width,height,orthogonal experiments were carried out,the introduction of the pier top deformation inhibition coefficient as evaluation index,the reinforcement effect by the variance analysis and significance test to identify the influence degree of various factors on the reinforcement effect,finally optimize the soil reinforcement is the key design parameters.The results show that pile length is a sensitive factor affecting the reinforcement effect when only isolation pile and longitudinal-transverse beams are used for reinforcement.The optimal pile length is 1.29 times of the buried depth at the bottom of the tunnel,and the settlement and longitudinal displacement inhibition coefficients are 0.856 and 0.843,respectively.When only MJS method is used for reinforcement,the length of the reinforced area is a sensitive factor affecting the reinforcement effect.The optimized reinforcement length is 6.11 times of the width of the bearing platform,and the settlement and longitudinal displacement inhibition coefficients are 0.748 and 0.787,respectively.When a single measure is used to strengthen the soil layer,isolation pile and longitudinal-transverse beams are preferred.When the isolation pile,vertical and horizontal beam and MJS method are used for reinforcement,the optimized pile length is still 1.29 times of the buried depth at the bottom of the tunnel,and the optimized reinforcement length is 4.56 times of the width of the cap.The settlement and longitudinal displacement inhibition coefficients are 0.947 and 0.950,respectively,which can satisfy the pier deformation control requirements for normal operation of high-speed railway trains on the bridge.It provides a reference for carrying out reasonable soil layer reinforcement design of the affected section by the large-diameter shield underneath the high-speed railway bridge.
Combined with the Tongjing Road North Extension Project in Suzhou,a finite element model of the whole construction process of 32 m simply supported box girder under a large-diameter shield was established.The effectiveness of the finite element model was preliminarily verified by comparing the field measured results with the numerical calculation results.Respectively isolated pile length,pile diameter,pile-tunnel clearance or MJS method strengthening regional factors such as length,width,height,orthogonal experiments were carried out,the introduction of the pier top deformation inhibition coefficient as evaluation index,the reinforcement effect by the variance analysis and significance test to identify the influence degree of various factors on the reinforcement effect,finally optimize the soil reinforcement is the key design parameters.The results show that pile length is a sensitive factor affecting the reinforcement effect when only isolation pile and longitudinal-transverse beams are used for reinforcement.The optimal pile length is 1.29 times of the buried depth at the bottom of the tunnel,and the settlement and longitudinal displacement inhibition coefficients are 0.856 and 0.843,respectively.When only MJS method is used for reinforcement,the length of the reinforced area is a sensitive factor affecting the reinforcement effect.The optimized reinforcement length is 6.11 times of the width of the bearing platform,and the settlement and longitudinal displacement inhibition coefficients are 0.748 and 0.787,respectively.When a single measure is used to strengthen the soil layer,isolation pile and longitudinal-transverse beams are preferred.When the isolation pile,vertical and horizontal beam and MJS method are used for reinforcement,the optimized pile length is still 1.29 times of the buried depth at the bottom of the tunnel,and the optimized reinforcement length is 4.56 times of the width of the cap.The settlement and longitudinal displacement inhibition coefficients are 0.947 and 0.950,respectively,which can satisfy the pier deformation control requirements for normal operation of high-speed railway trains on the bridge.It provides a reference for carrying out reasonable soil layer reinforcement design of the affected section by the large-diameter shield underneath the high-speed railway bridge.