U型盾构与明挖现浇建设电力隧道走廊的技术造价对比

电缆隧道已成为不少输电走廊的首选建设形式,由于明挖现浇隧道施工工艺较为成熟,因此以往大量的电力隧道以及综合管廊均采用此施工方案来实施。明挖现浇法存在施工断面及土方开挖量较大、施工环境不友好,施工效率较低等缺点。针对上述这些缺点,目前在雄安新区等地,开始采用U型盾构机械施工来取代明挖现浇电缆隧道施工。重点对比了两种施工方法的技术差异,同时比对了两种工艺的单位造价,并通过实际案例中工程量和造价的对比分析,给出了U型盾构施工工艺经济规模的大致路径长度。

综合管廊U型盾构机械化施工工法研究与应用

为解决传统明挖法、矿山法、盾构法和顶管法在综合管廊施工中存在的不足和局限,根据国内管廊工程建设环境特点,通过分析传统管廊施工方法的优点和不足,结合装配式建筑的发展趋势,创新性地提出U型盾构机械化施工工法。该工法将明挖法开挖与在盾壳内完成主体预制拼装结构相结合,通过研制相应装备将传统固定支护结构转变为刚性可移动支护结构,实现了明挖法管廊施工的机械化、标准化和规范化。介绍U型盾构工法的原理、适用范围、工艺流程、操作要点和节点处理,对比U型盾构与传统明挖支护结构的受力特点和对周边环境的影响,分析U型盾构适用范围及其工法优势;通过海口市椰海大道管廊试验,验证了该工法在明挖综合管廊施工中具有较高的进度优势、经济优势和推广应用价值;最后探讨该工法在小曲线半径、矩形或U型断面工程以及明挖框架结构工程中的应用前景,以期为综合管廊及类似工程提供一种新的设计理念和施工工法。

基于U型盾构施工的装配式综合管廊防水橡胶和预应力筋应力分析

U型盾构法施工开创了国内装配式综合管廊施工的新工法,具有安全、高效、经济、环保等技术优势。本文通过建立实体有限元模型,对U型盾构机械化施工中管廊、预应力筋以及防水橡胶等管廊重要部件之间协调作用进行模拟,提出了满足防水橡胶防水界面应力要求的预应力筋预变形,并针对管廊顶推过程中后置管廊对前置管廊的重要防水参数影响做出分析。

U型盾构推进力的计算与应用分析

U型盾构采用移动式盾体进行基坑支护,推进力是设计与应用环节中的重要参数之一。为解决U型盾构推进力的设计问题,以岩土力学和结构力学理论为基础,分析U型盾构在推进过程中推进阻力的产生原因和组成部分,建立U型盾构推进阻力的分项模型,分别对U型盾构推进时的侧部岩土及附加载荷产生的阻力、前部推板的推进阻力、自重摩擦阻力、爬坡阻力、盾尾与管节的摩擦阻力进行理论模型推导,结合地勘及设计参数对各分项阻力进行计算,并对各部分的构成占比进行分析。在实际工程应用中,分别检测统计出2种工况下的总推进力数据,并与理论计算进行比对。结果显示在2种工况下,理论模型的计算数据和实际检测的数据基本相符,表明计算模型的正确性,其分析方法及结果可为类似项目设计提供参考。

管廊明挖盾构施工关键技术研究与应用

为克服传统的综合管廊明挖法施工机械化程度低、对周边环境影响较大等不足,借鉴盾构法的技术优势,设计了一种应用于综合管廊明挖法施工的新型盾构及其施工工法。该工法将明挖法开挖与盾构法在盾壳内进行管节拼装相结合,提高了综合管廊明挖法施工的机械化和自动化程度。以海口市椰海大道综合管廊建设项目为依托,论述管廊明挖盾构的施工流程、管节之间防水抗渗问题的解决方案等。项目的成功应用为地下综合管廊的建设及类似工程提供了一种全新的施工装备和施工工法。

穿江底隧洞盾构机掘进方式复合衬砌设计

大型灌区或长距离调水工程穿越大江大河的江底隧洞是设计和施工的重难点。特别是穿越河段有通航或环保要求时,在河道内的施工将受到严格限制。随着施工设备和手段的进步,水利行业领域不断研究和采用更加安全可靠的施工技术。向家坝灌区北总干渠一期工程经综合技术经济比较,采用泥水平衡型盾构机掘进下穿岷江江底,充分利用盾构机的设备特点,对刀盘开口率、管片拼装、出渣方式等技术问题进行了相应研究。提出了“外水外承、内水内承”洞身复合衬砌结构设计原则,制定技术方案。为类似工程提供了良好的借鉴和参考。

地铁杂散电流场有限元模型与电路元件模型的对比仿真分析

对盾构型隧道地铁的杂散电流场进行建模并分别在均匀土壤和分层土壤的介质中通过加载不同的电流值进行仿真计算,将仿真结果与电路元件模型的仿真结果进行对比分析。对比分析表明,有限元模型能求出传统电路元件模型所不能求出的地下环境各个位置的电位情况,并且能对复杂的隧道结构以及复杂的地质条件进行仿真计算,因此有限元模型相比传统模型对研究杂散电流的防护范围更有效。

地铁常用隧道杂散电流场三维有限元模拟

基于地铁不同隧道类型对杂散电流场分布规律的影响,建立地铁矩形和盾构型隧道的杂散电流场三维有限元模型,通过加载电流,在不同地质条件下利用ansys有限元软件进行仿真分析。研究结果表明:钢轨及钢轨到周围地下环境的电位均呈非线性衰减趋势;加载的电流越大,不同隧道周围相同位置处的电位不同;在钢轨加载电流和隧道周围地质条件相同的情况下,矩形隧道比盾构型隧道向外泄漏的杂散电流少。

装配式钢结构反力墙受力分析研究

由中铁四局集团联合中铁装备集团研发制造的用于明挖基坑施工的U型盾构机,首次应用在海南省海口市椰海西延路段地下综合管廊施工项目。但是在U型盾构施工过程中,提供反力的反力墙无法重复使用,每阶段单独采用钢筋混凝土反力墙大大增加施工成本,鉴于这种优化思路,设计了一种可拆卸式钢结构反力墙,可供敞口式U型盾构顶进多次使用。对设计的钢结构反力墙进行受力检算分析,可为类似工程项目提供设计依据。

轨道交通盾构型车站公共区空调通风系统方案研究

轨道交通盾构型车站相比明挖、暗挖、矿山法车站,有着完全迥异的车站建筑布局。针对盾构型车站狭长、内部空间局促、管线压力大等特点,采取分散式空调加新风系统,根据公共区负荷特点,合理布局冷源位置。在气流组织上,采用流体力学模拟方法,提出了适合盾构型车站的空调通风方案。

Calculation of maximum surface settlement induced by EPB shield tunnelling and introducing most effective parameter

This study aims to predict ground surface settlement due to shallow tunneling and introduce the most affecting parameters on this phenomenon.Based on data collected from Shanghai LRT Line 2 project undertaken by TBM-EPB method,this research has considered the tunnel's geometric,strength,and operational factors as the dependent variables.At first,multiple regression(MR) method was used to propose equations based on various parameters.The results indicated the dependency of surface settlement on many parameters so that the interactions among different parameters make it impossible to use MR method as it leads to equations of poor accuracy.As such,adaptive neuro-fuzzy inference system(ANFIS),was used to evaluate its capabilities in terms of predicting surface settlement.Among generated ANFIS models,the model with all input parameters considered produced the best prediction,so as its associated R^2 in the test phase was obtained to be 0.957.The equations and models in which operational factors were taken into consideration gave better prediction results indicating larger relative effect of such factors.For sensitivity analysis of ANFIS model,cosine amplitude method(CAM) was employed; among other dependent variables,fill factor of grouting(n) and grouting pressure(P) were identified as the most affecting parameters.

Experimental study on the pressure control of soil chamber in shield tunneling

A mathematical model of the soil pressure system in shield tunneling was proposed to optimize soil pressure control in the soil chamber, based on the constitutive relationship between strain and stress. The desired pressure is determined by using the finite element method. A linear quadratic constant state tracking problem was considered over an infinite time interval. The optimal control law was derived by differentiating the Hamilton function with respect to system input. In order to verify the effectiveness of the proposed mathematical model and optimal control law, an experimental study on the pressure control of the soil chamber in shield tunneling was conducted in a laboratory. The experiment results show that soil pressure in the soil chamber in shield tunneling can be accurately controlled.

Numerical simulation study on the relationship between mining heights and shield resistance in longwall panel

A numerical model based on a Continuum-based Distinct Element Method(CDEM) was used to carry out a dynamic simulation of the interaction between shield and rock strata movement in longwall mining. In Northern China, the Ordos coal field geological conditions and operational characteristics were used as a case example. The CDEM was constructed on Ordos coal field shield's operation characteristics and geological conditions. Numerical modelling was carried out to investigate the effects of different mining heights on the caving process, movement characteristics, equilibrium and stability conditions of overburden as the interaction between shield and surrounding rocks. With the numerical model, the internal factors for changes in shield resistance under different mining heights was found. The quantitative relationship between mining heights and shield resistance was also obtained by the numerical simulation.

Prototype test study on mechanical characteristics of segmental lining structure of underwater railway shield tunnel

Based on the first unde rwater railway shield tunnel, the Shiziyang shield tunnel of Guangzhou Zhu- jiang River, the prototype test was carried out against its segmental lining structure by using ＂multi-function shield tunnel structure test system＂. And the mechanical characteristics of segmental lining structure using straight assembling and staggered assembling were studied deeply. The results showed that, the mechanical characteristics of segmental lining structure varied with the water pressures; especially after cracking, the high water pressure played a significant role in slowing down the growing inner force and deformation. It also testi- fied that the failure characteristics varied with straight assembling structure and staggered assembling structure. Shear thilurc often occurred near longitudinal seam when using straight assembling.

综合管廊机械化修建方法及展望

根据城市化快速发展下的综合管廊施工要求,针对U型盾构、矩形顶管机等典型综合管廊机械化施工方法,介绍了各施工案例项目背景,简述了各机械化施工设备的组成、工作方式及设计特点,同时重点论述了U型盾构、矩形顶管机机械化施工综合管廊的方法以及特殊施工技术要点。此外,讨论了现有的机械化设备在综合管廊建设中的适用性及优缺点,并对综合管廊机械化非明挖施工的发展提出了几点思考,为未来的综合管廊选择施工方法提供了借鉴。

Theoretical model for loads prediction on shield tunneling machine with consideration of soil-rock interbedded ground

The loads acting on shield tunneling machines are basic parameters for the equipment design as well as key control parameters throughout the entire operation of the equipment. In the study, a mechanical analysis for the coupled interactive system between the cutterhead and the ground at the excavation face is conducted. The normal and tangential loads acting on the cutterhead are decoupled and solved, with consideration of the influence of three key factors on loads: geological condition, operating status and equipment structure. Then analytical expressions for the thrust and the torque acting on the equipment under uniform geological condition are established. On this basis, the impact of soil-rock interbedded ground on acting loads is further considered. A theoretical model for loads prediction of earth pressure balance (EPB) shield machines working under soil-rock interbedded ground is proposed. This model is subsequently applied to loads prediction for a shield tunneling project under soil-rock interbedded ground. The computational value of the thrust and the torque, the measured loads and the load ranges from Krause empirical formula are compared. Thus, this model for loads prediction acting on shield tunneling machines under soil-rock interbedded ground has been proved to be effective.

Modeling and Prediction for the thrust on EPB TBMs under different geological conditions by considering mechanical decoupling

EPB TBMs(Earth pressure balance Tunneling Boring Machines) are extensively used in tunneling constructions because of its high efficiency and low disturbance on structures above ground. It is critically significant to predict the thrust acting on TBMs under different geological conditions for both the design of power system and the control of tunneling process. The interaction between the cutterhead and the ground is the core of excavation, through which geological conditions determine the thrust re-quirement combined with operating status and structural characteristics. This paper conducted a mechanical decoupling analysis to obtain a basic expression of the cutterhead-ground interactive stress. Then more engineering factors(such as cutterhead topological structure, underground overburden, thrusts on other parts, etc.) were further considered to establish a predicting model for the total thrust acting on a machine during tunneling. Combined with three subway projects under different geological conditions in China, the model was verified and used to analyze how geological, operating and structural parameters influence the acting thrust.