The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The re...The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.展开更多
Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation...Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.展开更多
超大断面隧道(断面面积大于100 m 2)开挖面积大,围岩扰动性强,因此常常需要进行超前支护控制隧道施工安全,管棚注浆加固是一种常见的隧道超前支护方式,其主要通过在隧道围岩上方形成注浆加固圈从而控制围岩应力和变形大小。在进行数值...超大断面隧道(断面面积大于100 m 2)开挖面积大,围岩扰动性强,因此常常需要进行超前支护控制隧道施工安全,管棚注浆加固是一种常见的隧道超前支护方式,其主要通过在隧道围岩上方形成注浆加固圈从而控制围岩应力和变形大小。在进行数值模拟计算过程中,注浆加固圈厚度是计算结果准确的关键。依托渝黔铁路张家山隧道工程,考虑管棚外插角和搭接长度对注浆加固圈厚度的影响,对传统计算公式进行优化,采用FLAC3D对比分析未使用管棚注浆加固和使用管棚注浆加固两种计算工况。结果表明:①优化后的注浆加固圈厚度计算公式与管棚外插角、浆液扩散半径、管棚长度、管棚纵向间距和环向间距5个参数相关,且使用优化后计算公式得到的数值模拟结果与现场监测数据更接近,计算结果更准确;②相较于未使用超前管棚注浆支护,使用超前管棚注浆支护拱顶沉降位移为12.65 mm,减小31.06%;③管棚注浆支护能够降低围岩竖向最大压应力20.72%和最大竖向拉应力44.68%,同时能够降低初期支护结构最大主压应力15.87%和最大主拉应力23.81%;④管棚注浆加固的地表沉降最大值为8.95 mm,较未使用管棚注浆加固减少24.25%;⑤管棚注浆加固效果与浆液扩散半径、管棚外插角和管棚长度呈正相关,与管棚纵向间距和环向间距呈负相关,其中浆液扩散半径影响效果最显著,管棚外插角影响最小。展开更多
文摘The first permanent magnet driven rectangular pipe jacking machine independently developed in China is used for the construction of pedestrian passage in Banxuegang Science and Technology City area of Shenzhen. The rectangular pipe jacking machine occupies a small area during the initial excavation. It is suitable for shallow soil covering and short-distance excavation. It is more economical and applicable than shield machine and has high construction efficiency. During the construction process, technical measures such as attitude measurement and adjustment of pipe jacking machine, surrounding rock grouting and friction reduction can effectively ensure the smooth construction of pipe jacking machine, and provide reference for large section pipe jacking machine in shallow soil construction.
基金Project(2022YJS073)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2024YFE0198500)supported by the National Key Research and Development Program of China:Intergovernmental International Science and Technology Innovation CooperationProject(U2469207)supported by the National Natural Science Foundation Railway Innovation and Development Joint Fund Project,China。
文摘Determining earth pressure on jacked pipes is essential for ensuring lining safety and calculating jacking force,especially for deep-buried pipes.To better reflect the soil arching effect resulting from the excavation of rectangular jacked pipes and the distribution of the earth pressure on jacked pipes,we present an analytical solution for predicting the vertical earth pressure on deep-buried rectangular pipe jacking tunnels,incorporating the tunnelling-induced ground loss distribution.Our proposed analytical model consists of the upper multi-layer parabolic soil arch and the lower friction arch.The key parameters(i.e.,width and height of friction arch B and height of parabolic soil arch H 1)are determined according to the existing research,and an analytical solution for K l is derived based on the distribution characteristics of the principal stress rotation angle.With consideration for the transition effect of the mechanical characteristics of the parabolic arch zone,an analytical solution for soil load transfer is derived.The prediction results of our analytical solution are compared with tests and simulation results to validate the effectiveness of the proposed analytical solution.Finally,the effects of different parameters on the soil pressure are discussed.
文摘超大断面隧道(断面面积大于100 m 2)开挖面积大,围岩扰动性强,因此常常需要进行超前支护控制隧道施工安全,管棚注浆加固是一种常见的隧道超前支护方式,其主要通过在隧道围岩上方形成注浆加固圈从而控制围岩应力和变形大小。在进行数值模拟计算过程中,注浆加固圈厚度是计算结果准确的关键。依托渝黔铁路张家山隧道工程,考虑管棚外插角和搭接长度对注浆加固圈厚度的影响,对传统计算公式进行优化,采用FLAC3D对比分析未使用管棚注浆加固和使用管棚注浆加固两种计算工况。结果表明:①优化后的注浆加固圈厚度计算公式与管棚外插角、浆液扩散半径、管棚长度、管棚纵向间距和环向间距5个参数相关,且使用优化后计算公式得到的数值模拟结果与现场监测数据更接近,计算结果更准确;②相较于未使用超前管棚注浆支护,使用超前管棚注浆支护拱顶沉降位移为12.65 mm,减小31.06%;③管棚注浆支护能够降低围岩竖向最大压应力20.72%和最大竖向拉应力44.68%,同时能够降低初期支护结构最大主压应力15.87%和最大主拉应力23.81%;④管棚注浆加固的地表沉降最大值为8.95 mm,较未使用管棚注浆加固减少24.25%;⑤管棚注浆加固效果与浆液扩散半径、管棚外插角和管棚长度呈正相关,与管棚纵向间距和环向间距呈负相关,其中浆液扩散半径影响效果最显著,管棚外插角影响最小。
