特殊地质条件下的TBM施工

采用全断面隧洞掘进机(TBM)施工方法快速、安全、效率高，但在特殊地质条件下所遇到的困难也是难以想象的。本文就山西省万家寨引黄工程施工中断层破碎带、蠕变岩体、溶洞、富水洞段等特殊地质条件下TBM施工进行了说明，可供同类工程参考和借鉴。     

全断面隧道掘进机的广泛使用及在掘进过程中可能发生的问题

本文对ＴＢＭ的广泛使用作了简要概述，并对ＴＢＭ在掘进过程中可能发生的问题和施工过程中可能产生的缺陷及缺陷产生的原因作了专门论述。     

基于钻孔过程监测的花岗岩钻进比能研究

为了探究钻进参数与岩石质量之间的相关性关系,并寻求一个能够定量描述岩体质量的参数,利用安装了DPM系统的SGZ-IIIA型取芯钻机对一块1.25 m×2.00 m×1.00 m的花岗岩进行了6次钻孔试验,对每个孔设置不同的推进压强和转速等参数(压强分为400 kPa、600 kPa、800 kPa三挡,转速分为128 r/min、200 r/min两档),根据钻进位移与钻进时间计算得出钻进速度。结果表明,对于同一种岩石,如果在钻进过程中,转速、扭矩、推进压力等钻进参数不同,那么钻进速度也会相应变化,无法仅利用钻进速度来定量描述岩体质量,无法发挥DPM的优势。通过理论分析与花岗岩试验结果可知,钻进耗能为1.11~1.83 kJ/cm~3,平均值为1.523 kJ/cm~3,基于能量守恒定律,引入钻进比能的概念,发现此参数与岩石物理力学强度参数相关性高,可以用来表征岩石质量,从而实现通过岩石钻进快速确定岩体质量。     

TBM施工组织管理技术

TBM隧洞施工是以掘进作业为核心,以掘进、支护、出渣运输为主要作业,通风、供电、供水、排水等为辅助作业进行的。它具有并行性、协调性、连续性和密集性等特点,这决定了TBM施工组织管理技术上的特殊性。为此,在TBM施工组织管理方面主要采取以下技术措施:(1)根据TBM施工特点,建     

Design and development of hydrogen isotope sensor in liquid PbLi

Indian LLCB – TBM uses liquid Lead-Lithium (Pb-Li) as tritium breeder, neutron multiplier and coolant. Tritium bred in liquid PbLi stream has to be recovered by tritium extraction system. Therefore, a reliable sensor with quick response time for measurement of hydrogen isotope is essential.A hydrogen isotope sensor in liquid Pb-Li, based on permeation of hydrogen isotopes through metal (sensor material) is designed. The capsule shaped sensor, made of iron membrane coated with Pd from inside (downstream side), allow hydrogen isotope to permeate through it. The design work mainly includes the selection of proper material, its thickness and surface conditions, which is to be supported by numerical calculations for optimization of maximum permeation flux, fast response and fabricability. The numerical calculation utilizes a physical model having recombination of two hydrogen isotope atoms at the surface and atomic diffusion through the bulk. In this work, design calculations based on numerical simulation and fabrication procedure of the hydrogen isotope sensor are presented.     

Development of a potential based code for MHD analysis of LLCB TBM

A two dimensional solver is developed for MHD flows with low magnetic Reynolds’ number based on the electrostatic potential formulation for the Lorentz forces and current densities which will be used to calculate the MHD pressure drop inside the channels of liquid breeder based Test Blanket Modules (TBMs). The flow geometry is assumed to be rectangular and perpendicular to the flow direction, with flow and electrostatic potential variations along the flow direction neglected. A structured, non-uniform, collocated grid is used in the calculation, where the velocity (u), pressure (p) and electrostatic potential (?) are calculated at the cell centers, whereas the current densities are calculated at the cell faces. Special relaxation techniques are employed in calculating the electrostatic potential for ensuring the divergence-free condition for current density. The code is benchmarked over a square channel for various Hartmann numbers up to 25,000 with and without insulation coatings by (i) comparing the pressure drop with the approximate analytical results found in literature and (ii) comparing the pressure drop with the ones obtained in our previous calculations based on the induction formulation for the electromagnetic part. Finally the code is used to determine the MHD pressure drop in case of LLCB TBM. The code gives similar results as obtained by us in our previous calculations based on the induction formulation. However, the convergence is much faster in case of potential based code.     

二次衬砌、辅助洞室开挖与TBM掘进三同步施工技术

隧道掘进机（TBM）是长大隧道施工最先进的设备,以往只能待TBM掘进贯通后施作辅助洞室以及二次模筑混凝土衬砌,这与新奥法施工原理不相符合。结合南疆铁路吐库二线中天山隧道TBM施工实践,实现了二次模筑衬砌、辅助洞室开挖与TBM掘进三同步施工技术,有助于加强隧道施工与工程质量的安全、缩短施工工期,具有较高的推广价值。     

Disc cutter wear prediction for a hard rock TBM cutterhead based on energy analysis

Disc cutter wear is a crucial problem that influences the working efficiency and security of hard rock tunnel boring machines (TBMs). This wear results from friction energy accumulation and conversion. In this study, the process of hard rock TBM disc cutter wear is identified and analyzed by quantifying the collective energy change. This study starts with an analysis of the friction process between the disc cutter and hard rock. The relationship between the rolling force work and thrust force work of the disc cutter is examined. As a result, the disc cutter energy equation is determined, and the meaning of the upper and lower bounds of this equation are discussed. Based on the above results, the hard rock TBM cutterhead energy equation is then deduced. A method to identify the friction work is developed. According to the energy wear theory, the cutter wear law on hard rock for a TBM cutterhead is revealed, and a method for predicting disc cutter wear for a hard rock TBM cutterhead is advanced. Furthermore, the validity of this prediction method is confirmed by utilizing data from project cases.     

超千米深部全断面岩石掘进机卡机机理

为了解决超千米深井巷道建设面临的严峻挑战,拟将全断面岩石隧道掘进机（TBM）在解决关键岩石力学问题和机械制造问题的基础上加以改进引入到超千米深井巷道建设。然而深部高应力挤压变形将导致TBM的护盾极易被卡塞。揭示了TBM的卡机机理：当护盾周围围岩变形量超过开挖预留的变形量,围岩开始与护盾接触并挤压护盾,进而在TBM推进时围岩对护盾产生摩擦阻力,当TBM推力无法克服围岩对护盾产生的摩擦阻力时,便导致TBM护盾被卡。提出了相应的卡机状态判据。提出了判断护盾被卡状态的理论计算方法及过程：考虑工作面空间效应,基于Hoek-Brown准则研究了护盾周围围岩收敛变形沿巷道轴向的变化规律,计算出作用在护盾上的围岩压力,进而计算围岩对护盾的摩擦阻力,最后根据卡机状态判据判断护盾是否被卡。     

TBM施工隧洞塑性变形围岩的处理与监测分析

文章介绍了大伙房水库输水工程TBM1施工段26+960-27+691洞段围岩发生塑性变形、侵占设计断面的处理措施,同时设计布置了永久性监测仪器。通过对仪器采集数据等相关资料的科学分析,表明该段隧洞围岩处于稳定状态。