坛厂隧道施工地质条件综合分析

坛厂隧道施工存在的主要工程地质问题是进口浅埋段岩堆及软土、两条大断层、岩溶及岩溶水、瓦斯。该四大问题集中于隧道进口端,致使隧道施工难度及风险性大大增加。对以上问题进行详细分析,并提出施工期综合地质超前预报技术方案和相应的施工建议。通过施工期地质超前预报的实施和隧道开挖验证,很好地指导了该隧道工程的安全施工,较好地解决了该隧道存在的复杂工程地质问题,保障了工程施工质量。     

深埋长隧洞地质超前预报技术

国内外已建成的各种不同用途的隧洞在掘进施工过程中常因发生不同程度的塌方、涌水、碎屑流、离地温、高地应力及岩爆、高瓦斯等地质灾害,考虑到我国近期有一系列深埋长隧洞工程,如南水北调西线工程、大伙房调水工程、锦屏二级水电站超深埋引水隧洞等急待建设工程,为避免施工过程中发生不可预见的地质灾害,故在工程施工过程中应加强地质超前预报工作,以减少投资风险．而提高预报的成功率则显得十分重要。     

震区地表破裂特征经验关系及其对隧道设计的意义

地震时活动断裂会对隧道产生巨大破坏,如何减轻地震对隧道的破坏,成为设计人员关注的热点问题。本文在研究大量关于震级与断层破裂参数及其位移量之间关系的基础上,利用 512 汶川地震的破裂参数进一步验证了Donald L.Wells等人关于震级与断层破裂参数和地表位移之间的经验关系式。结果显示,根据震级与地表破裂长度、地下破裂长度、破裂宽度以及平均位移的关系式得出的验证值与汶川地震的实际破裂参数相近,说明这些关系式可以在地震时估算破裂参数,并为地震区穿越潜在断层的隧道设计以及隧道安全性评价提供参考依据。     

华能宝兴电站引水隧洞富水涌泥断层破碎带施工中的 对策研究

华能宝兴电站引水隧洞工程开挖施工过程中,上游段遭遇T65断层带。因为这一断层破碎带的出现,该段曾发生4次突泥突水,严重影响了工程的进度。本文从工程地质角度研究该断层破碎带的工程特性,采用全断面帷幕注浆结合超前小导管注浆技术对富水涌泥断层破碎带进行加固止水,采用分步短进尺开挖,及时支护的方案进行隧道施工,保证了隧道施工的安全。该对策的有效实施为类似工程的施工起了一定的借鉴作用。     

在线示踪试验在隧道建设前期勘察中的应用研究以重庆城开高速公路拟建旗杆山隧道为例

由于岩溶含水介质具有高度不均一性和复杂性,给隧道建设带来很多不确定因素。本文以城开高速公路城口拟建旗杆山隧道为例,利用在线示踪技术,获取高分辨率示踪数据,结合定量解译的方法,分析隧址区岩溶地下水潜在的流向及其流场情况。本次在钻孔内注入投放示踪剂,开展示踪工作,通过试验结果查清了投放示踪剂位置地下水与水文单元内几个大型暗河的水力联系,为划分地下水分水岭和计算隧址区岩溶管道流水力梯度提供了有力依据,该成果极大地提高了隧址区水文地质调查工作的精度。通过本例,表明在线示踪技术在我国西南岩溶区的地下含水介质研究及相关的勘察中具有较大的推广和应用价值。     

马来西亚知玛达苏湖隧洞工程岩溶地质条件分析

知玛达苏湖隧洞工程位于马来西亚半岛西海岸最北部的玻璃市。研究区以岩溶地貌闻名,地塔状石灰岩丘陵十分常见。结合现场地质调查和前期有关资料,论文对隧洞工程穿越区域的地层岩性、地质构造、气象水文等进行简要介绍。在此基础上,从岩溶发育的基本必要条件出发,结合区域宏观岩溶及微观岩溶发育规律分析,应用分形理论开展岩溶发育程度评价和隧洞工程岩溶围岩分级评价,详细阐述隧洞工程施工可能面临的岩溶工程地质问题并提出相应的设计施工对策。隧洞工程的施工实践对岩溶地质条件分析结果进行了较好的验证,值得同类隧洞工程施工设计参考借鉴。     

Predicting the capability-polar-plots for dynamic positioning systems for offshore platforms using artificial neural networks

As the capability of polar plots becomes better understood, improved dynamic positioning (DP) systems are possible as the control algorithms greatly depend on the accuracy of the aerodynamic and hydrodynamic models. The measurements and estimation of the environmental disturbances have an important role in the optimal design and selection of a DP system for offshore platforms. The main objective of this work is to present a new method of predicting the Capability-Polar-Plots for offshore platforms using the combination of the artificial neural networks (NNs) and the capability polar plots program (CPPP). The estimated results from a case study for a scientific drilling vessel are presented. A trained artificial NN is designed in this work and is able to predict the maximum wind speed at which the DP thrusters are able to maintain the offshore platform in a station-keeping mode in the field site. This prediction for the maximum wind speed will be a helpful tool for DP operators in managing station-keeping for offshore platforms in an emergency situation where the automation of the DP systems is disabled. It is obvious from the obtained results that the developed technique has potential for the estimation of the capability-polar-plots for offshore platforms. This tool would be suitable for DP operators to predict the maximum wind speed and direction in a very short period of time.     

Some Attempts for Estimating Rock Strength and Rock Mass Classification from Cutting Force and Investigation of Optimum Operation of Tunnel Boring Machines

Summary. Tunnel face and wall collapse are common during excavations performed by tunnel boring machines (TBMs) due to the difficulty of correctly identifying the properties of the excavated rock. This identification, however, can be simplified by using the cutting force to estimate rock strength, a method that has already proved quite successful in Japanese tunnel excavations. This paper summarizes knowledge relating to the cutting force obtained through tunnel excavation experience, and the relationship between rock strength and TBM operation is discussed. Although TBM operators rely on intuition to set the cutter head speed appropriately, this decision process represents a logical method of operation that takes advantage of the variable speed capability of the cutter head. Selection of appropriate support methods for the excavated face is also a critical issue in tunnel excavation. This selection process is based on the condition of the rock, which is difficult to determine quickly and accurately during tunnel excavation. The present paper uses the excavation of two tunnels to demonstrate that it is possible to assign rock mass classifications accurately based on rock strength when boring a uniform rock type. It is also shown that the rock mass can be classified from the rock strength normalized by the uniaxial compressive strength when boring through mixed rock types.     

TSP超前地质预报探测技术及其应用现状

隧道工程的地质条件复杂多变,为了保证隧道施工安全和高效,超前地质预报探测就显得十分重要和必要。TSP是瑞士Amberg测量技术公司专门为隧道施工地质超前预报而设计的一套超前地质预报系统。与其他预报方法相比,该探测技术系统从数据采集、处理和成果解释等方面都具有一定的优势。本文从TSP原理、功能特点、技术发展、存在问题等方面对TSP作了系统阐述。并对TSP探测技术作了简要的总结,从而推广TSP在隧道施工中的应用。     

慈母山隧道施工涌水量预测

在水文地质调查的基础上,查明慈母山隧道施工期涌水来源主要为松散堆积层孔隙水、基岩风化裂隙水和碎屑岩孔隙裂隙水,通过抽水、注水、压水试验,获得慈母山隧道各段围岩体的渗透系数,应用地下水迳流模数法、大气降水渗入量法及地下水动力学水平坑道疏干法对施工期的隧道涌水量进行预测,并确定了各地层的涌水方式,提出施工期以堵为主的工程防治措施。