Machine learning-based automatic control of tunneling posture of shield machine

For a tunnel driven by a shield machine, the posture of the driving machine is essential to the construction quality and environmental impact. However, the machine posture is controlled by the experienced driver of shield machine by setting hundreds of tunneling parameters empirically. Machine learning(ML) algorithm is an alternative method that can let the computer to learn from the driver’s operation and try to model the relationship between parameters automatically. Thus, in this paper, three...     

Safety risk management of underground engineering in China:Progress,challenges and strategies

Underground construction in China is featured by large scale, high speed, long construction period,complex operation and frustrating situations regarding project safety. Various accidents have been reported from time to time, resulting in serious social impact and huge economic loss. This paper presents the main progress in the safety risk management of underground engineering in China over the last decade, i.e.(1) establishment of laws and regulations for safety risk management of underground engineering,(2) implementation of the safety risk management plan,(3) establishment of decision support system for risk management and early-warning based on information technology, and(4) strengthening the study on safety risk management, prediction and prevention. Based on the analysis of the typical accidents in China in the last decade, the new challenges in the safety risk management for underground engineering are identified as follows:(1) control of unsafe human behaviors;(2) technological innovation in safety risk management; and(3) design of safety risk management regulations. Finally, the strategies for safety risk management of underground engineering in China are proposed in six aspects, i.e. the safety risk management system and policy, law, administration, economy, education and technology.     

Latest progress of soft rock mechanics and engineering in China

The progress of soft rock mechanics and associated technology in China is basically accompanied by the development of mining engineering and the increasing disasters of large rock deformation during construction of underground engineering.In this regard,Chinese scholars proposed various concepts and classification methods for soft rocks in terms of engineering practices.The large deformation mechanism of engineering soft rocks is to be understood through numerous experiments;and thus a coupled support theory for soft rock roadways is established,followed by the development of a new support material,i.e.the constant resistance and large deformation bolt/anchor with negative Poisson’s ratio effect,and associated control technology.Field results show that large deformation problems related to numbers of engineering cases can be well addressed with this new technology,an effective way for similar soft rock deformation control.     

From the new Austrian tunneling method to the geoengineering condition evaluation and dynamic controlling method

The new Austrian tunneling method （NATM） is widely applied in design and construction of underground engineering projects. When the type and distribution of unfavorable geological bodies （UGBs） associated with their influences on geoengineering are complicated or unfortunately are overlooked, we should pay more attentions to internal features of rocks grades IV and V （even in local but mostly controlling zones）. With increasing attentions to the characteristics, mechanism and influences of engineering construction-triggered geohazards, it is crucial to fully understand the disturbance of these geohazards on project construction. A reasonable determination method in construction procedure, i.e. the shape of working face, the type of engineering support and the choice of feasible procedure, should be considered in order to mitigate the construction-triggered geohazards. Due to their high sensitivity to groundwater and in-situ stress, various UGBs exhibit hysteretic nature and failure modes. To give a complete understanding on the internal causes, the emphasis on advanced comprehensive geological forecasting and overall reinforcement treatment is therefore of more practical significance. Compre- hensive evaluation of influential factors, identification of UGB, and measures of discontinuity dynamic controlling comprises the geoengineering condition evaluation and dynamic controlling method. In a case of a cut slope, the variations of UGBs and the impacts of key environmental factors are presented, where more severe construction-triggered geohazards emerged in construction stage than those predicted in design and field investigation stages. As a result, the weight ratios of different influential factors with respect to field investigation, design and construction are obtained.     

Preliminary engineering application of microseismic monitoring technique to rockburst prediction in tunneling of Jinping Ⅱ project

Monitoring and prediction of rockburst remain to be worldwide challenges in geotechnical engineering.In hydropower,transportation and other engineering fields in China,more deep,long and large tunnels have been under construction in recent years and underground caverns are more evidently featured by ＂long,large,deep and in group＂,which bring in many problems associated with rock mechanics problems at great depth,especially rockburst.Rockbursts lead to damages to not only underground structures and equipments but also personnel safety.It has been a major technical bottleneck in future deep underground engineering in China.In this paper,compared with earthquake prediction,the feasibility in principle of monitoring and prediction of rockbursts is discussed,considering the source zones,development cycle and scale.The authors think the feasibility of rockburst prediction can be understood in three aspects：（1） the heterogeneity of rock is the main reason for the existence of rockburst precursors;（2） deformation localization is the intrinsic cause of rockburst;and（3） the interaction between target rock mass and its surrounding rock mass is the external cause of rockburst.As an engineering practice,the application of microseismic monitoring techniques during tunnel construction of Jinping II Hydropower Station was reported.It is found that precursory microcracking exists prior to most rockbursts,which could be captured by the microseismic monitoring system.The stress concentration is evident near structural discontinuities（such as faults or joints）,which shall be the focus of rockburst monitoring.It is concluded that,by integrating the microseismic monitoring and the rock failure process simulation,the feasibility of rockburst prediction is expected to be enhanced.     

中国的地下水利水电工程建设及TBM技术

This paper deals with the construction of underground hydraulic structures and TBM technology in China-past, present and future. China ranks number one in the world in water power. But, the ratio of developed to potential hydropower is only about 20%. The exploitable water power in West China, where is featured by high mountain and complex geology, accounts for 83% of the total for China. Most of the project structures have to be located underground.The projected length of hydraulic underground openings per year is about 180 km. Several underground projects completed, under execution and planned are highlighted in this paper. Finally, general information about the development of TBM technology in hydraulic construction in China is outlined.     

Engineering rock mechanics practices in the underground powerhouse at Jinping Ⅰ hydropower station

Based on the analyses of data obtained from the underground powerhouse at Jinping Ⅰ hydropower station,a comprehensive review of engineering rock mechanics practice in the underground powerhouse is first conducted.The distribution of strata,lithology,and initial geo-stress,the excavation process and corresponding rock mass support measures,the deformation and failure characteristics of the surrounding rock mass,the stress characteristics of anchorage structures in the cavern complex,and numerical simulations of surrounding rock mass stability and anchor support performance are presented.The results indicate that the underground powerhouse of Jinping Ⅰ hydropower station is characterized by high to extremely high geo-stresses during rock excavation.Excessive surrounding rock mass deformation and high stress of anchorage structures,surrounding rock mass unloading damage,and local cracking failure of surrounding rock masses,etc.,are mainly caused by rock mass excavation.Deformations of surrounding rock masses and stresses in anchorage structures here are larger than those found elsewhere:20%of extensometers in the main powerhouse record more than 50 mm with the maximum at around 250 mm observed in the downstream sidewall of the transformer hall.There are about 25%of the anchor bolts having recorded stresses of more than 200 MPa.Jinping Ⅰ hydropower plant is the first to have an underground powerhouse construction conducted in host rocks under extremely high geo-stress conditions,with the ratio of rock mass strength to geo-stress of less than 2.0.The results can provide a reference to underground powerhouse construction in similar geological conditions.     

Underground water biological field＇s variation and geoenvironmental safety in city

In the process of city construction, as a comprised factor of city geological environment, underground water takes the most active part, and its dynamic change is fiercest. The city construction unceasingly disturbs underground water chemical, dynamical, physical and biological field. In return, the four fields＇ changes also can affect the geological environment that city lived by, in other words they affect safety and stability of geological environment. Interaction of underground water and the geoenvironment directly displays in the following two ways： The first is that the underground water and the geological body transfer the energy each other; the second is that the strength balance of geological body is broken. Underground water variation brought about by city construction is the factor which cannot be neglected. Underground water variation on the one hand changes soils or rocks＇ physical, biological, chemical and mechanical properties, then influences the deformation and strength of geological body. On the other hand it changes its own physical, chemical properties and biochemical component. At present, from mechanics aspect, interaction between chemical field and biological field variation of the underground water and the geological body lacks research. Although interaction between them is long-term, slow, but when it compared with water-soil or water-rock interaction in the entire process of formation of rocks or soils or geologic evolution history, the qualitative change of the biological and chemical action of rocks or soils brought about by city construction is remarkable, in this paper, aiming at underground water biological field factor which is easily neglected by people, it analyzes that underground water biological field affects possible mechanism and approach of properties variation of rocks or soils in city construction, brings forward further research method and development direction have been also proposed.     

Geo-technical Instrumentation And Monitoring For Tuen Mun Station,West Railway,Hong Kong

Geo-technical instrumentation and monitoring is very important for the construction of civil works in urban area, by which the affect or even damage to the existing building and underground utilities in the working site or vicinity caused by construction activities can be predicted. During the construction of Tuen Mun station, West Railway, Hong Kong, series of Geo-technical instruments were installed and monitored in time, and the monitoring datawere transferred to the Geo-technical Monitoring System in the headquarter of the Employer promptly. Meanwhile, the alarming data were responded immediately and the modified construction methods have been adopted to avoid the damage to the building and underground utility in working site to ensure the smooth construction of the station.     

Risk assessment and management in underground rock engineering——an overview

This paper attempts to provide an overview of risk assessment and management practice in underground rock engineering based on a review of the international literature and some personal experience. It is noted that the terminologies used in risk assessment and management studies may vary from country to country. Probabilistic risk analysis is probably the most widely-used approach to risk assessment in rock engineering and in geotechnical engineering more broadly. It is concluded that great potential exists to augment the existing probabilistic methods by the use of Bayesian networks and decision analysis techniques to allow reasoning under uncertainty and to update probabilities, material properties and analyses as further data become available throughout the various stages of a project. Examples are given of the use of these methods in underground excavation engineering in China and elsewhere, and opportunities for their further application are identified.     

地下工程关键安全危险源识别

通过界定地下工程危险源概念,分析了危险源特征,对明挖法施工、盾构法施工和浅埋暗挖施工工艺中的关键危险源进行了辨识,得到各安全施工中需要重点关注的要点,从而为地下工程安全施工提供指导。     

盾构下穿越已运营隧道施工监测与技术分析

通过对上海M4线张扬路至浦电路区间隧道近距离下穿越已运营M2线工程施工过程的监测,分析对比了盾构两次近距离下穿越施工的过程和特点,讨论了M2线周围地层土体的沉降变形和规律。同时,针对盾构近距离穿越施工技术难题,较系统探讨了近距离下穿越施工技术方案,分析了施工技术控制要领,为今后类似工程提供了借鉴。     

基坑工程与地下工程 ——高效节能、环境低影响及可持续发展新技术

随着我国基坑工程和地下工程的建设规模和难度不断增大,基坑工程和地下工程相关技术取得了长足的进步。文章聚焦于近年来我国在高效节能、环境低影响、智能化控制及超深的基坑工程与地下工程方面的新技术的回顾与总结。在基坑工程领域,总结相关理论和方法、超深围护新技术、高效节能支护技术、环境低影响技术、智能化控制技术。在隧道工程领域,总结隧道失稳破坏模拟方法、地面出入式盾构隧道技术、类矩形盾构隧道技术、深层盾构隧道技术等。在地下工程预制装配式技术领域,总结预制装配式地下车站的研究和预制拼装结合现浇叠合拱壳的无柱大跨地铁车站建造技术的研究。以期藉此促进这些可持续发展的新技术的深入发展和应用。     

武汉剧院地下人行通道施工技术浅谈

针对武汉剧院地下人行通道工程埋深浅、路面活载作用频繁的特点,对明挖法、顶管法、盾构法和浅埋暗挖法进行了分析,根据工程特点及难点,确定采用浅埋暗挖法施工,并介绍了其具体施工方法,为类似工程提供参考借鉴。     

城市地下过街通道工程实例及分析

采用暗挖法修建城市地下过街道具有不干扰交通,无环境污染,地下管线拆迁少等优越性。本文介绍了几个工程实例的施工概况,阐述了暗挖法修建城市地下过街道的实践经验。     

弧形钢筋弯曲设备改制后的成功应用

结合三峡永久船闸地下输水系统工程和湖北清江水布垭工程地下厂房工程的特点及施工难题,介绍了弧形弯曲机的改进设计与制作方法,阐述了弧形机工作原理,并对其进行受力分析和强度验算,提出了施工过程中的注意事项。     

北京地区浅埋暗挖法下穿施工既有隧道变形特点及预测

 城市地下工程建设中,新建隧道近距离下穿施工对既有隧道造成的扰动不可避免。正确分析及可靠预计既有隧道变形成为目前地下工程建设的热点问题。在预测隧道开挖引起的地表位移的经验法中,Peck公式最简便,应用也最为广泛。搜集北京地区10个近接下穿工程23组数据,对既有隧道实测变形进行拟合,发现绝大多数符合Peck公式分布规律。拟合得到地层损失率为0.116%～1.183%,沉降槽宽度系数为0.93～6.76。讨论新建隧道施工工法、辅助施工方法、新建隧道与既有隧道的埋深、既有隧道刚度、新建隧道双洞间距、变形缝位置等因素对经验参数的影响,给出经验参数的修正公式。将经验参数修正公式与Peck公式相结合,为北京地区受新建隧道下穿施工影响的既有隧道变形提供一个简便、快捷的预测方法,并通过工程实例验证了预测方法的有效性。研究成果可对未来北京同类工程和其他地区近接工程设计和施工提供参考,同时对丰富同类工程数据库具有重要意义。     

隧道工程施工过程风险因素研究

隧道工程施工过程蕴含复杂、多样的风险因素,但目前相关研究尚不完善。本研究应用问卷调查的方法,对采用矿山法施工的隧道工程项目施工过程中的风险因素进行识别和分析,总结出施工过程中重要的风险因素,为隧道工程项目施工过程的风险管理提供依据。     

超大直径盾构下穿棚户区沉降控制技术研究

超大直径盾构下穿老旧棚户区微扰动施工控制是地下工程实践中面临的重要难题。本文以武汉地铁8号线黄浦路站—徐家棚站区间盾构下穿棚户区项目为工程背景,首先对提出全断面粉细砂层注浆加固工艺并进行浆液配比实验给出最佳浆液配比,并对盾构施工过程进行实时监测监控,根据工程具体情况对盾构机下穿掘进参数进行分析,最后提出超大直径泥水盾构穿越棚户区施工的控制措施。研究结果表明:袖阀管注浆加固工艺对超大直径盾构下穿的老旧棚户区具有较好的保护作用,现场试验确定最佳水灰配比为0.8∶ 1;盾构穿越过程中地表沉降纵向变化呈近似U型分布,横向变形出现明显沉降槽,加固棚户区老旧结构基础最大隆起值为15 mm,建筑结构整体先隆起后减弱,且沉降值控制在15 mm以内;盾构机总推力和刀盘扭矩、盾构机总推力和土舱压力、出土率和土舱压力具有变化规律一致性。研究结果为揭示超大直径盾构下穿老旧棚户区施工过程对地层和地面建筑结构的影响规律提供参考和依据。     

盾构隧道下穿高速公路加宽区管桩施工技术

以郑州地铁3号线出入场线-新柳路站盾构施工为工程背景。研究小半径、大纵坡、浅覆土盾构隧道下穿高速公路加宽区管桩的施工技术。本文将盾构下穿高速公路加宽区分为三个过程,即盾构机达到管桩前、盾构机下穿管桩过程中和盾构机穿过管桩后进行研究。在盾构机到达管桩前设试推段,以确定适当的土仓压力、掘进速度和同步注浆参数;在盾构下穿管桩过程中调整适当的推进方向和姿态控制、管片拼装、注浆参数和防渗措施;以及对盾构穿过管桩后的监测及加固措施等进行研究,有效地保证了隧道的成型效果及盾构施工的顺利进行。