TBM自重对围岩变形影响的数值模拟研究

为研究双护盾全断面隧道掘进机(TBM)自重对围岩变形的影响,基于FLAC3D有限差分软件,通过改变隧道的埋深与围岩条件,建立3种工况数值模型,并对每个工况分别进行了考虑TBM自重与不考虑其自重的数值模拟,以对比各种工况下有无TBM自重作用的隧道围岩纵向位移曲线(LDP曲线);研究了TBM自重对围岩变形的影响。模拟结果表明,TBM自重可抑制隧道围岩的径向位移,并随着开挖隧道的围岩等级升高、埋深变浅,其自重对围岩变形的影响越大,且与不考虑TBM自重的围岩变形相比,边墙洞壁的径向位移减小率最大,仰拱与拱顶次之。这些认识对研究TBM与围岩的相互作用和预测卡机有重要意义。     

Prediction of TBM jamming risk in squeezing grounds using Bayesian and artificial neural networks

This study presents an application of artificial neural network(ANN) and Bayesian network(BN) for evaluation of jamming risk of the shielded tunnel boring machines(TBMs) in adverse ground conditions such as squeezing grounds.The analysis is based on database of tunneling cases by numerical modeling to evaluate the ground convergence and possibility of machine entrapment.The results of initial numerical analysis were verified in comparison with some case studies.A dataset was established by performing additional numerical modeling of various scenarios based on variation of the most critical parameters affecting shield jamming.This includes compressive strength and deformation modulus of rock mass,tunnel radius,shield length,shield thickness,in situ stresses,depth of over-excavation,and skin friction between shield and rock.Using the dataset,an ANN was trained to predict the contact pressures from a series of ground properties and machine parameters.Furthermore,the continuous and discretized BNs were used to analyze the risk of shield jamming.The results of these two different BN methods are compared to the field observations and summarized in this paper.The developed risk models can estimate the required thrust force in both cases.The BN models can also be used in the cases with incomplete geological and geomechanical properties.     

全断面隧道掘进机刀盘裂纹尖端应力强度因子收敛性分析

针对全断面隧道掘进机刀盘裂纹损伤及寿命预测等工程问题,提出了基于子模型技术的应力强度因子求解方法,并用含裂纹的矩形钢板对该方法进行了验证,分析了裂纹网格参数对刀盘裂纹尖端应力强度因子的收敛性影响。结果表明,钢板的应力强度因子数值和理论计算结果最大相对误差为3.6%。同时得到了保证刀盘应力强度因子求解精度和效率的裂纹单元网格参数,为结构的裂纹扩展寿命预测提供了参考。     

管片衬砌配合陶粒可压缩层支护结构型式的模型试验研究

提出一种适用于深部地层TBM工法隧道的管片衬砌配合陶粒可压缩层的让压支护技术,结合台格庙矿区TBM施工的长距离斜井工程,采用模型试验方法,从管片衬砌弯矩、轴力、变形、破坏特征对比分析陶粒和碎石可压缩层的让压效果,从可压缩层的压缩变形路径和颗粒移动特征角度揭示各自的让压机制。研究结果表明：陶粒内部蜂窝状构造使其具备高压缩性,压缩率是碎石的10倍;陶粒可压缩层的让压效果要优于碎石可压缩层;不等压地应力条件下,碎石可压缩层会在一定程度上减小管片衬砌负弯区的抗力系数,导致负弯矩偏大,负弯区裂纹数量和宽度增加。陶粒和碎石的形状和内部构造差异导致两者让压效果和机制不同,最终导致管片衬砌的内力和变形、破坏特征差异。陶粒可压缩层让压机制由相互嵌挤、错动移位和挤压破碎作用三部分组成;碎石可压缩层的让压机制由前两部分组成;不等压地应力件下,由于陶粒的圆形形状特征,其向地应力较小侧自由移位和挤压作用发挥程度要高于菱角状外形的碎石,这一特征不仅增加了陶粒的让压效果还会在一定程度上增大了地应力较小侧的地层抗力系数,改善了管片衬砌受力特性。研究结果对未来TBM工法修建深部斜井的支护结构型式设计具有一定参考价值。     

TBM隧道综合超前地质预报及其在阳灵隧道的应用

超前地质预报对于实现隧道施工的信息数据化,灾害防治的有效化,施工支护的经济化等方面具有不可代替的作用。对比分析钻爆法中的超前地质预报方法在隧道掘进机(tunnel boring machine, TBM)特定的施工环境下使用的有效程度,提出综合“长短距离、物探钻探、声波电磁、重点平时”的TBM隧道施工下的超前地质预报体系的构想,并基于水平声波剖面法(horizontal sonic profiling, HSP)声波反射法、钻孔过程监测系统(drilling process monitoring, DPM)超前钻探、瞬变电磁仪等方法,利用三维正演计算的理论研究,进而压制了单一超前地质预报方法的多解性和误差叠加性,从而提高预报的精确度和可靠性。基于本研究的电磁响应规律以及去除电磁干扰研究,指导宜兴阳灵隧道瞬变电磁法的实际工程应用,并对预报结果进行总结对比,从而为今后工程提供借鉴参考。     

长隧道中隧道掘进机的应用

对长隧道中应用隧道掘进机的现状、典型实例、问题以及发展趋势作了论述     

水利工程隧洞掘进机施工概算定额编制方法探讨

水利工程输水隧洞采用掘进机施工已较普遍,但国内仍没有一套完整可依据的隧洞掘进机概算定额,因此编制一套定额对合理确定相关工程概（估）算投资具有重要的现实意义。介绍了掘进机施工概算定额及施工机械台时费定额编制的基本思路和方法,阐述了定额测算方法及工程取费费率测算方法。     

深井煤矿TBM组装硐室变形破坏机理及控制对策北大核心

为研究深井煤矿TBM组装硐室围岩破坏机理和优化其支护方案,以张集煤矿TBM组装硐室施工为工程背景,建立块体离散单元法数值模型,开展数值模拟,分析TBM组装硐室围岩变形破坏机理;基于现场监测数据与数值模拟结果,揭示TBM组装硐室变形破坏机理,采用了以全锚索支护和硬化底板为主的组装硐室修护与支护优化方案。结果表明:选用的组装硐室支护优化方案有效控制了围岩破坏和变形,且施工工艺简单,对TBM组装、始发工作影响较小。     

Vibrations induced by tunnel boring machine in urban areas: In situ measurements and methodology of analysis

Excavation with tunnel boring machine (TBM) can generate vibrations, causing damages to neighbouring buildings and disturbing the residents or the equipment. This problem is particularly challenging in urban areas, where TBMs are increasingly large in diameter and shallow in depth. In response to this problem, four experimental campaigns were carried out in different geotechnical contexts in France. The vibration measurements were acquired on the surface and inside the TBMs. These measurements are also complemented by few data in the literature. An original methodology of signal processing is proposed to characterize the amplitude of the particle velocities, as well as the frequency content of the signals to highlight the most energetic bands. The levels of vibrations are also compared with the thresholds existing in various European regulations concerning the impact on neighbouring structures and the disturbance to local residents.     

适应复杂多变地质隧道双结构TBM研制与应用

川藏铁路隧道建设面临着高原高寒、地形高差大、地质条件复杂等方面严峻挑战，应用全断面隧道掘进机（Tunnel Boring Machine）是高效建成川藏铁路隧道的有效途径之一，但常规TBM已无法满足复杂地质多变隧道施工要求。为保障TBM安全、高效施工，提出了一种适应极端复杂地质环境的新型双结构TBM，首先，探讨了不良地质下传统TBM的适应性，分析了敞开式TBM在极端复杂地质环境下隧道变形机理；进一步地，针对不良地质下敞开式TBM施工痛点，基于常规敞开式TBM结构，开展了预留超前地质预报接口、主机结构增强、强化支护能力和清渣能力、释放地应力、安全防护措施等一系列创新性设计，并建立了常规地质“网-喷-锚”敞开支护和不良地质“钢管片-辅推”封闭支护的双结构支护体系；最后，依托于色季拉山项目，评价了双结构TBM在不良地质条件下的适应性，现场整体掘进率表明，应用效果良好。对于解决TBM复杂地质条件下施工有一定的借鉴意义。