隧洞围岩分类与洞径和超欠挖之间的关系研究

岩体的地质结构特征是影响隧洞围岩超欠挖的主要因素,正确评价岩体的质量,对岩体进行分类,并研究岩体质量与隧洞超欠挖之间的关系对分析和预测隧洞超欠挖具有重要的意义。对隧洞围岩的RMR分类和Q分类与超欠挖之间的关系进行了详细研究,研究了在同类岩体条件下不同开挖洞径与隧洞超欠挖之间的关系,并由此建立了RMR分类和Q分类之间的关系,得出围岩的RMR分类和Q分类与隧洞超欠挖呈线性关系和对数线性关系,根据超欠挖建立起来的RMR分类和Q分类之间的关系比较符合工程实际。最后研究了超欠挖与围岩分类及洞径之间的复相关关系。     

喷锚支护在水工隧洞施工中的应用浅说

简要地介绍了对水工地下洞室施工中对围岩不稳定体,即碎裂岩体、松动岩体、软弱结构面、楔形体结构面等围岩喷锚支护结构的作用,喷锚支护结构的使用。     

某抽水蓄能电站PD_6平洞超挖调查与评价

本文通过某抽水蓄能电站输水隧洞的勘探平洞 PD6 的超挖测绘调查 ,分析了平洞超挖块体的边界条件 ,确定了超挖块体的类型及其特征 ,利用自编计算程序 ,评价了各类型超挖块体的体积及其分布模型。这对于地下洞室超挖的评价方法以及工程建设中地下洞室稳定性评价以及加固处理具有一定指导意义。     

盘石水库泄洪洞、导流洞岩体工程地质特性研究

盘石水库泄洪洞、导流洞所涉及的岩体为寒武系下统灰、页岩互层层状岩体。其中页岩对洞室的稳定起决定作用。本文采用多种方法对洞室围岩特别是页岩进行了研究。取岩块,挖平洞、竖井做实验,研究其强度和变形特征,观察有无软弱夹层对洞室稳定的影响,在此基础上进行基本质量级别分级。进而分析、归纳出影响洞室稳定的主要因素及洞室设计力学参数,对同类工程具有类比和借鉴的意义。     

白山水电站地下洞室的几个岩体稳定问题

围岩稳定性的评价是地下建筑中的一个重要课题,由于影响因素较多和地质情况的复杂,迄今尚未得到令人满意的解决。本文通过白山电站地下洞室设计和施工中所遇及的几个岩体稳定问题及其工程处理,对地下洞室围岩稳定性的分析评价提出了一些看法。文中认为,在坚硬的块状岩石中,地下洞室的围     

某抽水蓄能电站PD6平洞超挖调查与评价

本文通过某抽水蓄能电站输水隧洞的勘探平洞ＰＤ６的超挖测绘调查,分析了平洞超挖块体的边界条件,确定了超块体的类型及特征,利用自编计算程序,评价了各类型挖块体的体积及其分布模型,这对于地下沿室超挖的评价方法以及工程建设中地下洞室稳定性评价以及加固处理具有一定指导意义。     

利用岩石化学成分预测岩浆型铜镍（铂）矿方法的提高和改进

在地质成矿规律研究的基础上，利用电脑对国内外代表性的含铜镍(铂)矿基性超基性岩体岩石化学成份排列组合计算找矿参数。将含矿岩体参数与经详细地质工作证实的无矿岩体参数对比，筛选有找矿意义参数建立《找矿决策模型》。利用该模型对会理会东地区基性超基性岩体进行预测。结果发现杨合伍、李家湾、黄土坡等值得进一步工作岩体。其认识与地质条件分析吻合。其中黄土坡是本次预测新提出的找矿靶区。     

用统计分析方法研究燕山岩带隐伏基性—超基性岩体赋存的地质地球物理模式

本文旨在燕山岩带作决策模拟的基础上进一步缩小预测隐伏基性一超基性岩体的耙区。通过选择能充分表征预测岩体的航磁异常一次标志,组合标志构成多个变量作多元统计分析,提取与预测岩体密切相关的信息,圈定岩体异常并进行分类。从而建立本区基性超基性岩体的地质地球物理模式以及评价其找矿意义。     

关于利用岩石化学成分预测岩浆型铜镍(铂)矿方法的讨论

在地质成矿规律研究的基础上,利用计算机对国内外代表性的含铜镍(铂)矿基性、超基性岩体岩石化学成份排列组合计算找矿参数;筛选有效的找矿参数建立“找矿决策模型”。利用该模型对会理、会东地区基性—超基性岩体进行预测,发现杨合伍、李家湾、黄土坡等岩体值得进一步工作;其中黄土坡岩体是本次预测新提出的找矿靶区。     

金丽温高速公路连拱隧道超挖预测及原因分析

通过对金丽温高速公路连拱隧道的地质特征进行现场调查,经分析得出隧道区岩体结构面的特征参数,利用分析出的结构面特征参数值,结合隧道超挖预测中的神经网络理论及结构面网络模拟理论,对连拱隧道的超挖情况进行预测。从分析结果看,超挖问题在连拱隧道的施工过程中不可避免,其产生部位主要集中在中导洞与隧道的连接部位,通过预测得出的结果与现场开挖情况进行对比分析说明,隧道的超挖预测理论预测结果与实际有较好的一致性,文中最后针对隧道的特点,分析了产生超挖的基本原因,为确保隧道开挖过程中减少超挖提供依据。     

节理岩体中地下洞室超挖计算

讨论了超挖的定义以及不稳定块体体积与超挖的关系 ,总结了计算块体位置和体积的方法可分为随机、确定性和半概率方法三类 ,为今后超挖方面的研究提出了指导方向。重点分析并给出了被三个节理面切割的岩块以及隐含危险岩块的位置计算的确定性方法 ,提出了岩块体积计算简易的近似算法。超挖计算对洞室安全、高效地现场施工具有重要指导意义.     

块体理论在高速公路连拱隧道超挖预测中的应用

通过对金丽温高速公路连拱隧道区的结构面特征进行现场调查,经统计分析得出结构面的特征参数,利用分析出的结构面特征参数值,结合块体理论,对连拱隧道的超挖情况进行预测。首先介绍了块体理论在超挖预测中运用的基本方法,推导了最大块体体积的计算公式,通过编制的计算程序对金丽温高速公路2个连拱隧道的超挖块体大小及位置进行预测。从分析的结果看,超挖问题产生部位主要集中在中导洞与隧道的连接部位,预测的结果与实际情况基本一致。通过预测得出的结果证实了块体理论在高速公路连拱隧道超挖预测中的适用性。     

Blast overbreak measurement by light sectioning

Summary In this new method for measuring the cross-section of tunnels and other excavations, the opening is outlined by a plane of light projected from a conical mirror. The image is recorded on videotape, enhanced, then measured by microcomputer. The measured profile is compared automatically with the specified profile to give values for overbreak and underbreak.Trials in Mexican tunnels and at an underground mine in Canada have evaluated the technique in relation to traditional mechanical, photographic, and surveying alternatives. Results indicate that the light sectioning method requires less than a minute per profile and no surveying skills. Costs are low, and the measurements are accurate to within a centimetre or two. Using the same photoanalysis technique and software, rock quality can be measured at the same time and place as overbreak, which helps the engineer to decide whether overbreak is caused by geological conditions or by deficiencies in blasting.     

差异风化型危岩力学模型及破坏机制研究

差异风化型危岩多形成于由砂岩和泥岩等软、硬岩性组成的互层陡倾岩质边坡中,其崩塌破坏属地质灾害中的常见形态。以普洱渡危岩高边坡为例,推导出差异风化型危岩岩腔后壁泥岩压应力随岩腔深度增加而增大的计算公式。据普洱渡危岩高边坡地形地貌和地质构造特征建立了两类4种差异风化型危岩力学模型：第1类为主控结构面贯通率等于1时的泥岩基座压裂破坏型和转动破坏型危岩;第2类为主控结构面贯通率小于1时的坠落型和倾倒型危岩。利用岩石强度理论推导出研究区砂岩的二次抛物线型摩尔强度包络方程,以极限平衡理论和摩尔强度理论推导了4种危岩体在自重、地震力和裂隙水压力共同作用下的崩塌破坏判别表达式,并由此反演出危岩体的临界崩塌边界方程,得出危岩体崩塌边界（岩腔深度、危岩体厚度和高度、主控裂隙深度）之间的关系,为现场预测和判别危岩体的稳定性和崩落时序提供简便可靠的依据。     

Predicting Overbreak from Blast Vibration Monitoring in a Lake Tap Tunnel - A Success Story

Tunnels are required to be constructed for meeting different human needs such as power generation, transportation, underground storage, sewage etc. The predominant method of excavation, world over, is drilling and blasting owing to its capability to meet changing geo-technical conditions. Irrespective of the purpose for which the tunnels are driven, all are plagued by overbreak problems. Tunnels driven for water conveyance in hydroelectric power projects, in particular, need to be excavated with minimum overbreak to minimise cost of permanent concrete lining. Thus, predicting overbreak assumes significant importance to design site-specific blasts for minimizing rock damage. This paper presents a brief review of existing PPV (Peak Particle Velocity) based blast-induced rock damage estimation criteria and attempts to outline the ground vibration threshold levels for overbreak/rock damage in a tunnel driven through compact basalt. Rock damage manifested as overbreak is measured and correlated with the possible threshold levels of PPV. Also, the PPV levels for crack initiation and widening are proposed. The case pertains to a lake tap horizontal tunnel of Koyna Hydro-electric Power Project, India which is a water feeder tunnel for a fully underground hydroelectric power project. The tunnel was driven under a shallow rock cover of average depth ranging from 20 to 25m beneath a fully charged water body. The parting rock is mainly compact basalt. Blasting was carried out in two rounds in a controlled manner, i.e., by limiting the maximum charge per delay based on ground vibration monitoring. Ground vibration generated with free face (in second round) has been modeled and a new ground vibration propagation equation is proposed for tunnel blasting including the effect of an extra free face. The threshold limits of PPV for different degrees of overbreak/rock damage are proposed from extrapolated vibration predictor equation. The actual overbreak in the tunnel, measured using a Planimeter, varied from 2.45 per cent to 17.75 per cent of the finished tunnel area. The predicted overbreak from extrapolated PPV measurements is compared against the measured overbreak to validate the proposed blast-induced rock damage (BIRD) assessment model. The PPV level for overbreak was found to exceed 2050 mm/s in compact basalt. A linear relationship between the overbreak and maximum charge per delay is also established to design a tunnel blast in similar formations.     

图像处理技术在隧洞超欠挖评价中的应用

图像处理技术在隧洞超欠挖评价中的应用是该技术在地质及岩土工程领域的新尝试。通过对野外摄取的隧洞图像进行一系列的处理得到隧洞的基本形状,然后与隧洞的设计形状对比分析,即可得到隧洞在该断面上的超欠挖方量,然后对其他断面采用同样的技术就可评价某一段或整个隧洞的超欠挖数量,这样就从定量的角度解决了以往工程中难以解决的超欠挖评价问题,为工程超欠挖的判断与决策提供合理依据。最后通过一实例对某一隧洞的超欠挖方量进行评价。     

Effects of joint orientation and rock mass quality on tunnel blasting

It is a well known fact that rock mass properties influence the process of fragmentation considerably. Model blasts and field investigations were carried out to find the effects of rock mass quality and joint orientation on tunnel blasting. Propagation of shock waves are partially restricted by joint planes. It was observed that the blast results (i.e., average fragment size and depth and cross-sectional area of the broken zone) were considerably influenced by joint orientation. Accordingly, it has been concluded that loading equipment with a larger capacity and deeper blast holes are required in formations with joint planes perpendicular to the tunnel axis. The number of blast holes, however, should be greater when joints are parallel to the tunnel axis. Furthermore, the powder factor (kg/m³) has been found to be directly related to rock mass quality (Q). Optimisation of pull, powder factor and overbreak is required in the case of weak formations with joints perpendicular to the tunnel axis. The use of contour blasting technique seems to be essential in poor and fair rock masses to minimise the overbreak, reduce the support cost and improve the stability of the opening.