软土地层土压平衡盾构施工参数的模型试验研究

我国沿海经济发达城市及一些内陆中心城市正在兴建或筹建地铁,这些地区的地下广泛分布着较厚的软黏土沉积层。为研究土压平衡盾构在这种软土地层中施工的适应性,以上海地铁M8线某区间隧道工程为研究背景,采用室内模型试验的方法,开展在不同埋深、不同刀盘开口率、不同推进速度以及不同螺旋机转速等情况下的盾构掘削模型试验。通过对试验结果的整理与分析,得出土仓压力与排土效率、单位时间排土量与推进速度、推力和扭矩之间的内在联系,以及隧道埋深、刀盘开口率、推进速度对推力和扭矩的影响。这些结论的取得为盾构施工参数之间及其与地层特性之间的适应性理论提供了有益的帮助,并为更好地指导软土地层盾构隧道的设计与施工服务。     

土压平衡盾构掘进中的止水技术

通过广州地铁4号线仑头-大学城盾构区间隧道的工程施工实践,总结了解决土压平衡盾构机掘进过程中螺旋输送器喷涌和盾尾刷密封处漏水这一常见问题的几点关键技术。     

软土地层土压平衡盾构法施工的模型试验研究

我国沿海地区以及许多内陆城市的地下广泛分布着很深的软黏土沉积层,目前该区域的许多城市都已兴建或正在筹建地铁。为确保在这种软弱地层中能采取与之相适应的盾构工法、减少对周围环境的影响以及降低工程造价,以上海地铁M8线某区间隧道工程为研究背景,采用室内模型试验的方法,进行了土压平衡盾构针对软土地层的适应性试验研究。为此,首先根据相似理论和模型试验方法建立了土体–盾构机器之间的相似系统;随后,针对上海地区特定的软土地层,进行了人工模型土壤的配制和模型试验方法的设计,并利用直径400 mm的模型盾构机模拟直径6340 mm的原型盾构机;最后,进行盾构不同工作参数组合的掘削试验,并记录下试验过程中机器工作参数及土体内应力和变形变化的有关试验结果,通过对试验数据的整理与分析,得出了软土地层中土压平衡盾构法施工的一些有用的规律。     

土压平衡盾构法施工参数的模型试验研究

由于受地质条件和施工工艺的限制,盾构掘削参数的变化难免会对地层产生扰动影响,往往由此而引发一系列的环境病害问题,故而有必要开展土体-盾构系统的基础试验研究。首先进行了盾构模型试验方案的设计,该方案包括直径0.4 m的土压平衡模型盾构、2.4 m×2.4 m×1.2 m的试验土箱、盾构工作驱动系统和数据采集系统等4部分;随后在软硬不同的模型土层中,进行盾构不同工作参数组合的掘削试验,得出一些有用的规律。     

富水砂卵石地层土压平衡盾构掘进渣土改良技术

土压平衡盾构机在富水砂卵石地层掘进过程中,由于土体流塑性差,土舱内的渣土无法及时排出,导致推进速度缓慢,盾构推力及刀盘扭矩增大等现象,易出现地表塌陷事故.为此,文章以成都地铁17号线一期项目盾构隧道工程为背景,进行砂卵石地层土压平衡盾构隧道施工土体改良试验研究.试验结果表明:采用泡沫剂或泡沫剂+膨润土作为土体改良剂对砂...     

地铁隧道土压平衡盾构始发掘进施工技术

盾构始发掘进作为地铁隧道施工的关键,关系着后续掘进施工的顺利开展以及隧道的建设质量、实际进度,故须绝对重视。文章基于某地铁隧道土压平衡盾构始发掘进施工实际,就盾构始发掘进各阶段的施工技术要点展开探讨,以供借鉴参考。     

土压平衡式盾构施工工艺：上海合流污水工程隧道掘进施工技术

介绍上海合流污水治理工程概况、所采用的从日本引进的土压平衡式盾构掘进机和后续台车、皮带输送机、管片机及其它配套设备的技术参数及其施工工艺。     

小口径土压平衡盾构江底隧道与曲线掘进施工技术

本文详细介绍了国内首条最小直径及最小转弯半径盾构隧道施工技术,其中对盾构在黄浦江江底出洞、进洞;盾构出洞克服急剧变化的坡度;盾构穿赵黄浦江最汪覆盖土;盾构水平曲线最小转弯半径的施工;隧道导线测量等关键技术作了阐述。     

天津地铁标段土压盾构掘进参数控制研究

依托天津地铁11号线一期工程,对盾构始发与标准段的土舱压力、出渣量、掘进速度等掘进参数控制进行探讨。对整个掘进区间的掘进参数进行分析,结果表明,总推力在7800～31000kN之间,刀盘转矩在600～3150kN·m之间,推进速度在35～55mm/min之间,每环注水量为0.5～1.2m³,各参数稳定在合理区间,验证了掘进参数控制合理性。     

土压平衡盾构掘进的数学物理模型及各参数间关系研究

为保证开挖面稳定及控制地面沉降,土压平衡盾构掘进时必须合理匹配各施工参数。基于模型试验结果,推导土压平衡盾构的3个基本方程式,进而得到土压平衡盾构2个总平衡方程式,建立土压平衡盾构掘进的数理模型。在此基础上推导总推力、土仓压力、螺旋机转速、掘进速度间关系的数学表达式,利用盾构施工的现场数据验证关系式的正确性。利用现场掘进数据统计刀盘扭矩、刀盘转速、土仓压力间的经验关系式。这些关系对土压平衡盾构设计时的参数选择和匹配有重要的指导意义,可以应用于土压平衡盾构施工时的参数控制。土压平衡盾构掘进的连续性方程为土压平衡盾构掘进时的地面沉降控制提供了新的研究思路。     

Experimental study on working parameters of earth pressure balance shield machine tunneling in soft ground

Deep sedimentary deposits of soft clays are widely distributed in coastal areas as well as many interior major cities in China. In order to study the stratum adaptability of earth pressure balance (EPB) shield machine tunneling in such types of soft ground, model tests of tunneling excavation, using the running tunnel of the Shanghai Metro Line M8 as a background, are carried out with different over burden ratios, opening rates of cutter head, driving speeds and rotation speeds of screw conveyor. Based on the test results, the interrelationships between chamber pressure and mucking efficiency, mucking rate and driving speed, thrust force and torque are obtained. The influences of tunnel depth, opening rate of cutter head and driving speed on thrust force and torque are revealed. Such findings can not only facilitate establishing relationships between shield working parameters and soil properties, but also serve as a guide for the design and construction of shield tunnel in soft ground. __________ Translated from China Civil Engineering Journal, 2007, 40(9): 87–94 [译自: 岩土工程学报]     

Model test and discrete element method simulation of shield tunneling face stability in transparent clay

The stability of the shield tunneling face is an extremely important factor affecting the safety of tunnel construction. In this study, a transparent clay with properties similar to those of Tianjin clay is prepared and a new transparent clay model test apparatus is developed to overcome the “black box” problem in the traditional model test. The stability of the shield tunneling face (failure mode, influence range, support force, and surface settlement) is investigated in transparent clay under active failure. A series of transparent clay model tests is performed to investigate the active failure mode, influence range, and support force of the shield tunneling face under different burial depth conditions, whereas particle flow code three-dimensional numerical simulations are conducted to verify the failure mode of the shield tunneling face and surface settlement along the transverse section under different burial depth conditions. The results show that the engineering characteristics of transparent clay are similar to those of soft clay in Binhai, Tianjin and satisfy visibility requirements. Two types of failure modes are obtained: the overall failure mode (cover/diameter: C/D≤1.0) and local failure mode (C/D≥2.0). The influence range of the transverse section is wider than that of the longitudinal section when C/D≥2.0. Additionally, the normalized thresholds of the relative displacement and support force ratio are 3%–6% and 0.2–0.4, respectively. Owing to the cushioning effect of the clay layer, the surface settlement is significantly reduced as the tunnel burial depth increases.     

盾构施工引起地表沉降的影响因素分析

在Loganathan公式的基础上,利用正交试验方法,分析了盾构施工中注浆填充率、支护压力比、偏心率、盾构埋深4个因素对地表沉降的影响程度,分析结果可以为施工提供重要的指导。     

Force transmission characteristics for the non-equidistant arrangement thrust systems of shield tunneling machines

Earth Pressure Balance shield tunneling has been successfully adopted for urban tunneling and has resulted in increases in working speed, savings of man-hours and improved safety. Based on the ellipse eccentricity, the ellipse matrix equation for non-equidistant systems has been constructed. Through the analysis of the matrix, the characteristics of force ellipse eccentricity were investigated in detail. The distinction from the equidistant system was studied by applying the force ellipse to the thrust systems of shield machines in engineering applications. It provides a new arrangement for the thrust system hydraulic cylinders, under large change-of-direction forces or uneven geological bodies, which may prevent the segments from cracking due to an over-offset load.     

Prediction of shield tunneling-induced ground settlement using machine learning techniques

Predicting the tunneling-induced maximum ground surface settlement is a complex problem since the settlement depends on plenty of intrinsic and extrinsic factors. This study investigates the efficiency and feasibility of six machine learning (ML) algorithms, namely, back-propagation neural network, wavelet neural network, general regression neural network (GRNN), extreme learning machine, support vector machine and random forest (RF), to predict tunneling-induced settlement. Field data sets including geological conditions, shield operational parameters, and tunnel geometry collected from four sections of tunnel with a total of 3.93 km are used to build models. Three indicators, mean absolute error, root mean absolute error, and coefficient of determination the (R²) are used to demonstrate the performance of each computational model. The results indicated that ML algorithms have great potential to predict tunneling-induced settlement, compared with the traditional multivariate linear regression method. GRNN and RF algorithms show the best performance among six ML algorithms, which accurately recognize the evolution of tunneling-induced settlement. The correlation between the input variables and settlement is also investigated by Pearson correlation coefficient.     

Artificial neural networks for predicting the maximum surface settlement caused by EPB shield tunneling

Numerous empirical and analytical relations exist between shield tunnel characteristics and surface and subsurface deformation. Also, 2-D and 3-D numerical analyses have been applied to such tunneling problems. Similar but substantially fewer approaches have been developed for earth pressure balance (EPB) tunneling. In the Bangkok MRTA project, data on ground deformation and shield operation were collected. The tunnel sizes are practically identical and the subsurface conditions over long distances are comparable, which allow one to establish relationships between ground characteristics and EPB – operation on the one hand, and surface deformations on the other hand. After using the information to identify which ground- and EPB-characteristic have the greatest influence on ground movements, an approach based on artificial neural networks (ANN) was used to develop predictive relations. Since the method has the ability to map input to output patterns, ANN enable one to map all influencing parameters to surface settlements. Combining the extensive computerized database and the knowledge of what influences the surface settlements, ANN can become a useful predictive method. This paper attempts to evaluate the potential as well as the limitations of ANN for predicting surface settlements caused by EPB shield tunneling and to develop optimal neural network models for this objective.     

盾构掘进过程中影响刀盘磨损因素研究

针对沈阳地区砂土地层的盾构刀盘磨损研究较少的现状，以沈阳地铁一号线5标启工街至保工街段左右两条线为背景，对与刀盘磨损相关的掘进参数进行了统计分析，提出了刀盘扭矩的建议取值，从而有效指导盾构施工。     

盾构进站接收险情处理的探讨

地铁盾构进站接收施工是地铁盾构施工中的重点和难点,属于重大风险源,本文以福州地铁工程为实例,对地铁盾构进站接收的险情处理从地质情况、抢险措施、事故原因等进行介绍和分析,为今后地铁盾构施工遭遇类似的情况提供参考借鉴。