盾构推进液压系统的PLC控制

介绍了盾构推进液压系统的工作原理.研制了以可编程控制器(PLC)为核心的盾构推进液压控制系统.对控制系统的硬件结构、软件组成、控制方式和控制策略等作了详细介绍,实现了对推进液压系统的运动控制,达到了预定的控制要求.     

盾构隧道运营期结构安全关键技术研究

由于地质、设计、施工、材料性能、环境变化等方面的原因,隧道的运营安全问题日益突出,将直接影响隧道的正常使用性能。本文在盾构隧道运营期特点分析的基础上,就盾构隧道共性的结构安全监测、结构安全性能评估及养护维修等关键技术进行了分析,供相关工程结构安全问题参考应用。     

Improved analytical model for circumferential behavior of jointed shield tunnels considering the longitudinal differential settlement

Differential settlements of the shield tunnel along the longitudinal direction can significantly affect the circumferential behavior of segmental lining, degrading both the structure safety and serviceability. In this paper, the authors introduce both the shearing effect and flattening effect on the tunnel cross section, which was caused by the longitudinal differential settlement, into an existing analytical model of jointed shield tunnels. An example is then presented to illustrate the variation of the circumferential behavior of segmental lining, including both the structure safety and serviceability, along the longitudinal position. Finally, a series of parametric studies are performed to investigate how factors such as tunnel longitudinal settlement, property of surrounding ground, and the design parameters of segmental lining affect the circumferential behavior of the segmental lining.     

Risk analysis using fault-tree analysis (FTA) and analytic hierarchy process (AHP) applicable to shield TBM tunnels

In this paper, the potential risk of undesirable events occurring during tunneling with application of a shield tunnel boring machine (TBM) method is discussed along with the risk analysis which can systematically assess overall risk levels. Potential risks and typical scenarios pertaining to shield TBM tunnels have been investigated based on previous case histories and correspondence with experts. The relevant risks from undesirable events were categorized into four groups: cutter-related malfunction, machine blockage or hold-up, mucking problems that hinder transporting excavated materials, and segment defects. A fault-tree set was constructed by grouping risk factors (or causes) into geological, design and construction/management factors. Risk analysis was performed by adopting fault-tree analysis (FTA) and an analytic hierarchy process (AHP) with consideration of the probability and impact of the risks. In addition, the proposed method was reliably validated by comparison with field observation, and thus indicates its applicability to risk management for shield TBM tunneling.     

盾构法隧道的纵向受力分析

本文借助等效连续化模型 ,把盾构法隧道假设为弹性地基上的弹塑性梁 ,着重研究了纵向不均匀荷载、不均匀沉降对隧道应力分布以及缝隙张开状况的影响。并以某越江隧道为工程实例 ,分析了隧道的受力变形。     

Development of a prestressed and precast concrete segmental lining

Prestressed & precast concrete segmental lining (P&PCSL) is used for shield tunnels. Its primary feature is that it integrates segments into one ring by introducing prestress in the tunnel circumferential and longitudinal directions. Introducing prestress enables the elimination of bolt joints and reduces the volume of reinforcement, thus reducing the manufacturing cost of precast concrete segments. It also enables quality improvement and labor saving in lining and provides greater adaptability for tunnels with large diameter, where deformation due to dead load is a problem. The P&PCSL has been implemented in three construction projects after undergoing various performance tests and workability verification tests.     

Causes of reduction in shield TBM performance - A case study in Seoul

This study investigates the fundamental reasons of reduction for excavation performance on shield TBM in the Han River riverbed tunnel by means of analysis of field measurement data. For the study: (1) measurement data were analyzed by both the thrust and penetration rate data in a given section with rock types and direction types, (2) a number of disk cutter consumption and types of abrasion were analyzed, (3) an exhaust ratio of screw conveyor and design problem of screw conveyor were analyzed by earth mud which becomes the rock powder. As a result of this study, it was found that the lack of penetration depth caused by lower thrust, disk changes according to rapidly changing rock types, and installed angle of screw conveyor, play an important role in the excavation performance.     

Deformational responses of operated shield tunnel to extreme surcharge: a case study

A field case of operated shield tunnel disrupted by unexpected extreme surcharge in Shanghai is reported in this paper. The deformational responses of segmental lining, in terms of convergences, settlements and joint open width, are highlighted. The surcharge caused by unexpected dumped soils with a maximum height of 7 m is six times larger than the design value of surcharge. Three hundred and sixty segmental lining rings of the operated metro shield tunnel below this surcharge are severely affected. The measured horizontal convergence to outer-diameter ratio (ΔD/D_out) ranges from 16.6 to 35.7‰, which is far beyond the averaged value for normal condition, i.e. 5.1‰. The trend of tunnel deformation (e.g. horizontal convergence and settlement) varying with surcharge level is found to be significantly non-linear. Correspondingly, the longitudinal joints are also severely disrupted and have large open widths. The rubber packer for joint near-tunnel springline loses its function of waterproof due to the release of 6 mm pre-compressive deformation. The majority of steel bolts of joint near-tunnel crown have passed yield state, while some are fractured. However, the circumferential joints are found to be in a sound workability.     

地铁盾构穿越京广线股道群控制措施及效果分析

研究目的：随着城市地铁建设日渐增多,地铁施工所面临的穿越各种既有运营线路的问题也随之增多。为了进一步了解盾构穿越既有运营线路的影响,本文根据某城市地铁施工实际情况,主要针对地铁盾构穿越既有铁路线时采取的各项控制措施,以及采取控制措施后各项变形情况进行分析。研究结论：地铁盾构穿越京广线股道群时,为减小对铁路运营的影响主要在于施工中采取的各种控制措施,本文通过本区间穿越期间对沉降进行分析,虽然在盾构穿越期间造成地表、轨枕、道床沉降量较大,但通过各种控制措施合理施工,确保了穿越期间铁路运营安全。     

双单元建筑物的换气速度和内部流动的测量

采用示踪气体稀释法对选定的双单元建筑物的换气速度和内部流动进行了测量,以期建立一种实际测量的方法,同时获得一些有用的数据。测量结果表明,选定的建筑物具有令人满意的换气速度,内部流通良好,可满足室内空气质量的要求,但对污染事故的屏蔽能力较差。本工作可以为研究室内空气质量和建筑物屏蔽因子提供一些借鉴。