隧道施工对邻近结构物影响评价软件的开发

隧道修建过程中不可避免扰动周围地层,对邻近结构物和地下管线产生不利影响,严重时甚至会使结构发生破坏,造成重大经济损失和安全事故.针对隧道施工对邻近结构物的影响,开发了一套施工对邻近结构物影响评价的软件系统.通过该评价系统,用户可以采用多种方法预测隧道开挖引起的地层位移,并在此基础上对建筑物和管线损害情况进行系统评价.实...     

A simplified analysis method for the influence of tunneling on grouped piles

One of key issues of tunneling in urban areas is to assess the likely impact on adjacent piled buildings of tunnel construction. Simple and reliable predictions of tunneling-induced bending and axial stresses in pile foundations are important to the safety of tunneling. In this paper, a simple two-stage analysis method for determining the response of pile groups caused by tunneling was presented. At the first stage, an analytical solution proposed by Loganathan and Poulos [Loganathan, N., Poulos, H.G., 1998. Analytical prediction for tunneling-induced ground movement in clays. J. Geotech. Geoenviron. Eng., ASCE 124 (9), 846–856] is used to estimate the free-field vertical and lateral soil movements induced by tunneling. At the second stage, assuming no slippage at the soil-pile interface, the Winkler model is first adopted for simulating the pile-soil interaction, combined with finite difference method in the case of multi-layered soils. Then, shielding effect is considered for the interaction between two passive piles using a logarithmic attenuation function suggested by Randolph and Wroth [Randolph, M.F., Wroth, C.P., 1979. Analysis of the vertical deformation of pile groups. Géotechnique 29 (4), 423–439] for vertical response and Mindlin’s solution for lateral response. Finally, the response of a passive pile group due to tunneling is obtained by the superposition principle. Solutions obtained by the proposed approach for the analysis of single piles and piled groups subjected to ground movements induced by tunneling are compared with those using the boundary element program GEPAN. Comparisons are also made between the observed behavior of centrifuge model tests as well as field measurements and those computed by the proposed method. It is demonstrated that the present method can in general give a satisfactory prediction of the response of passive piles subjected to tunneling.     

地层位移引起建筑物变形特性分析

城市深基坑开挖或地铁隧道掘进会引起附近建筑物或其他结构的变形,对建筑物变形特性的研究对于建立符合实际的变形预测方法和变形风险预估体系有着至关重要的实际意义。长期以来对由于地层位移引起的建筑物变形特点的研究尚比较少,特别是在岩土工程的相关研究范畴。在理论分析的基础上,提出一个判定建筑物变形特性(弯曲或剪切)的方法,并提出"弯曲变形率"指标以量化判定结构物变形特性。通过对伦敦地区两栋建筑物实际变形数据的研究,发现建筑物基本以剪切变形为主。在后续的分析中,进一步说明在一般情况下由于开挖引起邻近多层或高层建筑物的结构变形均以剪切变形为主,这与一般在分析和计算中假定结构主要以弯曲为主不同。基于此,认为结构的剪切刚度是其变形的主要控制因素,而非弯曲刚度。最后基于建筑物实测变形数据反算得到实际建筑物的结构刚度比E/G,由此获得对建筑物的实际变形特性更加深入的认识。     

Response analysis of nearby structures to tunneling-induced ground movements in clay soils

This study examined the effects of tunneling-induced short-term ground movements on nearby structures in clay soils considering the soil–structure interactions of different tunnels, structures, ground, and construction conditions. The investigation relates the level of structural distortion and damage to different tunnel field conditions. For this purpose, extensive numerical parametric studies were conducted, and the results were compared with field cases. The discrete element method (DEM) was used to model structural cracking when the shear and tensile stress exceeds the maximum shear and tensile strength. Brick-bearing and brick-infilled frame structures were considered, and the distortion and cracking induced in the structures were related to different tunnel field conditions. A relationship was developed to correlate the ratios of the tunnel depth to the diameter (Z/D) and ground loss conditions with the level of structural damage for different ground and structure conditions. The study results were integrated into a design framework in engineering practice. The relationship developed was compared with observed field cases, and the results indicated that it can be used practically to assess the structural damage in the design stage of tunnel constructions in a range of tunnel field conditions in clay soils. The study results provide a background for better understanding of how to control and minimize the damage of a structure to tunneling-induced ground movements in clay soils under different tunnel, structure, ground, and construction conditions.     

Building response to tunnelling

Understanding how buildings respond to tunnelling-induced ground movements is an area of great importance for urban tunnelling projects, particularly for risk management. In this paper, observations of building response to tunnelling, from both centrifuge modelling and a field study in Bologna, are used to identify mechanisms governing the soil–structure interaction. Centrifuge modelling was carried out on an 8-m-diameter beam centrifuge at Cambridge University, with buildings being modelled as highly simplified elastic and inelastic beams of varying stiffness and geometry. The Bologna case study presents the response of two different buildings to the construction of a sprayed concrete lining (SCL) tunnel, 12 m in diameter, with jet grouting and face reinforcement.In both studies, a comparison of the building settlement and horizontal displacement profiles, with the greenfield ground movements, enables the soil structure interaction to be quantified. Encouraging agreement between the modification to the greenfield settlement profile, displayed by the buildings, and estimates made from existing predictive tools is observed. Similarly, both studies indicate that the horizontal strains, induced in the buildings, are typically at least an order of magnitude smaller than the greenfield values. This is consistent with observations in the literature. The potential modification to the settlement distortions is shown to have significant implications on the estimated level of damage. Potential issues for infrastructures connected to buildings, arising from the embedment of rigid buildings into the soil, are also highlighted.     

地铁区间施工周边环境安全风险评估方法研究

城市地铁施工通常规划在市区繁华地带,往往需下穿城市居住区和办公区,施工条件及周边环境复杂,不确定性因素多,容易对周边环境造成较大影响,是一项高风险建设工程,因此需要在地铁工程的施工过程中对周边环境进行风险评估,从而采取相应的风险控制措施。本文提出了一个基于相关向量分类机和贝叶斯网络的概率风险评估方法,针对地铁施工特点结合历史数据和专家经验,通过专家知识表达和数据分析描述风险影响因素的风险传播路径和影响程度,对地铁施工过程中引起的周边建筑物、管线等环境安全风险进行风险分析,从而作为安全措施的指导依据。该分析方法应用在武汉地铁二号线某一盾构隧道区间内,分析结果表明了该模型作为一种风险评估方法的可行性。     

砂卵石地层土压力平衡盾构施工开挖面稳定及邻近建筑物影响模型试验研究

盾构技术在砂卵石地层中应用越来越多,砂卵石地层具有很强的不确定性特征,盾构施工的关键问题之一是保持开挖面稳定性及减小地面沉降。利用土压平衡盾构模型,研究北京砂卵石地层中不同埋深时邻近建筑物影响下的开挖面稳定性及地表沉降规律。试验中,分析柔性基础邻近建筑物及埋深对开挖面极限支护力和地表沉降的影响,揭示开挖面稳定性、土拱效应与极限支护力及地表沉降的关系。在邻近建筑物影响下,砂卵石地层中的支护压力呈非对称分布,且砂卵石地层中盾构推进引起的沉降值大于基于Peck公式的计算值,研究成果对砂卵石地层中盾构施工有重要的指导意义。     

地铁隧道施工邻近建筑物安全风险等级评价

根据武汉地铁工程实际经验,分析了地铁隧道施工邻近建筑物安全风险评估流程,基于建筑物与隧道的邻近等级划分、建筑物现状评价、隧道工程条件等因素,将地铁施工邻近建筑物安伞风险等级划分为5级,提出了地铁施工邻近建筑物安全风险等级划分方法和标准,为对不同风险等级建筑物给出相应的控制标准和施上保护措施提供依据.     

Application of new urban tunneling method in Baikoh tunnel excavation

This paper reports a new mountain tunneling method which yielded good results in Baikoh Tunnel construction. Since tunnels in urban areas, in many cases, are driven through soft ground with groundwater and in locations close to various utilities and structures, maintaining the structural stability of not only the tunnels but also such nearby existing structures is of utmost importance. In order to solve these problem, two methods have been developed: an auxiliary method to restrict displacements which consists of the special jet grouting for foot piles and the long steel pipe forepiling, and a boring method for groundwater drainage which does not cause adverse effects on tunnel construction. Using these methods in combination, the new mountain tunneling method is a useful means for constructing tunnels with shallow overburden in soft ground in urban areas. This method is called the new urban tunneling method. This method is cost-effective compared with other tunneling methods, especially for short urban tunnels with shallow overburden. Therefore, this method will be used in many future tunnel projects in urban areas subjects to various restrictions.     

城市暗挖隧道穿越既有结构物的安全性控制

当前,我国以城市轨道交通建设为主导的城市地下空间开发已进入高潮。在城市地下工程建设中,由于城市环境复杂、线网规划密集以及建设时间的先后顺序不同,穿越和邻近既有建（构）筑物的情况不可避免。本文针对城市暗挖隧道近距离穿越不同类型既有结构物的安全影响及其控制问题进行了系统研究,明确了新建隧道-岩土体-既有结构之间的动态相互作用关系,重点分析了不同结构的应力响应、变形响应特点,进而对结构安全性响应进行了分析,并针对穿越施工高风险的特点,建立了以变形控制为核心的工程安全风险控制体系,形成了相应的控制流程和技术模式。     

遮拦叠交效应下地铁盾构掘进引起地层沉降分析

 地铁隧道施工诱发的土体沉降以及临近地下构筑物变形是我国城市轨道交通施工安全控制和风险评估中较为关心的一类施工问题。目前,针对该领域地层沉降的简化理论研究还仅仅针对自由位移场,没有考虑临近既有构筑物的遮拦效应影响。依托上海在建地铁施工工程实践,采用简化理论方法、三维有限元数值模拟方法以及现场监测方法,分析考虑运营隧道遮拦效应影响的土压平衡盾构施工引起的周围土体沉降规律,并与自由位移场条件下盾构施工引起的地层变形进行对比分析;在此基础上,给出地铁盾构复杂叠交穿越引起的临近地铁隧道的变形规律。研究表明,本文提出的简化理论方法和三维有限元数值模拟方法可以较好地模拟遮拦叠交效应下地铁盾构掘进引起的地层沉降变形;临近既有建(构)筑物施工,盾构施工引起的周围土体沉降较大程度地受到遮拦效应影响,与自由位移场条件下的计算结果对比存在较大差别。最后,结合盾构施工监测数据,提出复杂遮拦叠交效应下的盾构叠交施工变形控制技术措施。成果可为合理制定施工场地存在复杂建(构)筑物工况条件的地铁隧道开挖对周围环境保护措施提供一定的理论依据。     

双线盾构施工对邻近建筑物影响的数值分析

 城市繁华地区盾构隧道施工常需从建筑下方地层穿越,如何确保上部建筑及隧道安全是施工中的难题。以武汉长江双线盾构隧道工程为例,利用有限元程序ABAQUS,对穿越武汉理工大学5层钢筋混凝土框架结构电教楼下方的隧道盾构掘进采用三维数值分析方法进行计算,模拟盾构掘进引起的地层变形和规律以及对隧道上部建筑物的影响。计算预测值与实测值较吻合,分析方法可用于分析和预测盾构掘进引起地层及隧道上部建筑物的变形。     

盾构掘进对隧道周围土层扰动的理论与实测分析

在城市环境中，如何控制地层移动以保证隧道周围临近建筑物以及地下市政设施等的安全，是设计以及施工中必须考虑的主要问题。通过对盾构施工对地层扰动的一般性状的分析认为，地层的移动在盾构隧道周围呈现区域性的不同特征，而且随工作面压力的不同，各扰动区域间的分界面发生变化。另外。由于已有地下污水管道自身具有一定的刚度，它的存在对盾构掘进引发的地层移动产生一种遮拦作用而使地层移动特征发生变化。以上海地铁二号线工程为工程背景，通过在地下污水管道周围的地层中测定地层的超孔隙水压力和土层的移动(包括地层的分层沉降以及地层在两个方向的水平位移)。研究了盾构法隧道穿越地下污水管道时盾构推进与地层移动的相关性。研究表明，在盾构掘进接近、穿越以及远离测孔区3个施工阶段，隧道周围不同区域的土层呈现出各自不同的移动特征。     

在建民用建筑火灾风险评估模型构建及应用

为客观评估在建民用建筑消防安全状况,构建并应用了一套实用性较强的火灾风险评估模型。分析在建民用建筑火灾特点以及致灾因素,构建在建民用建筑火灾风险综合评价体系。应用层次分析法确定各层级权重,利用模糊综合评价法进行综合评判,建立不同施工阶段在建民用建筑火灾风险评估模型。应用该模型对某在建民用建筑进行安全评估,指导火灾隐患整改,并对整改前后安全风险进行对比。评估结果表明,在建民用建筑最大风险因素为用火用电管理,此结论与实际状况较为相符。     

Probabilistic approach to assessing and monitoring settlements caused by tunneling

Tunnel construction commonly causes deformations of the surrounding ground, which can endanger buildings and other structures located in the vicinity of the tunnel. The prediction of these deformations and damages to buildings is difficult, due to limited knowledge of geotechnical conditions and due to uncertainty in predicting the response of the structures to the settlements. This motivates the development of a probabilistic model for the prediction of tunneling-induced damage to buildings. We propose such a model, based on the classical Gaussian profiles for the approximation of the subsidence trough and the equivalent beam method for modeling the response of the building walls. In practice, settlements are commonly monitored through deformation measurements. To account for this, we present a Bayesian method for updating the predicted settlements when measurements are available. Finally, we show how maximum allowable settlements, which are used as threshold values for monitoring of the construction process, can be determined based on reliability-based criteria in combination with measurements. The proposed methodology is applied to a group of masonry buildings affected by the construction of the L9 metro line tunnel in Barcelona.     

地铁盾构隧道下穿建筑基础诱发地层变形研究

城市繁华地区地铁盾构隧道施工常需从建筑基础下穿越，如何确保上部建筑与隧道结构安全是施工中的难题。基于沉降预测理论及FLAC3D进行了地铁施工诱发地层环境损伤评估与控制设计STEAD系统的开发，以广州地铁区间隧道下穿某7层框架结构建筑为例，采用数值模拟研究了地铁盾构隧道穿越建筑基础诱发地层变形的空间效应问题，考虑了不同工况下隧道施工引起地层沉降对该建筑物的影响，采用本研究建议，盾构隧道成功穿越该建筑物，实测证实了变形空间效应研究的科学性与有效性。     

盾构掘进对周围环境的影响分析

盾构机在城市地铁建设中得到了广泛的应用,但在盾构掘进过程中会引起地层损失,过大的地层损失,可导致较大的地面沉降,对地面建筑物、地下管线等设施产生不利影响甚至会导致破坏,引起较大的经济损失。为此,本文以实际工程为例,对盾构掘进过程中引起的建筑物、地下管线位移以及引起的地下水位进行了监测,得到了规律性的结论。     

城市隧道开挖对地表建筑物影响的安全评价

以青岛胶州湾海底隧道青岛端接线工程开挖为研究对象,根据其受隧道施工影响的程度分成很邻近（极邻近）、邻近、较邻近和不邻近4个等级,提出了划分标准以及邻近地铁建筑物沉降及倾斜的计算方法．基于建筑物破坏等级和建筑物重要性将邻近建筑物安全风险等级划分为3级,提出了上部建筑的破坏等级、重要性和安全风险等级之间的对应关系．提出房屋损坏三阶段评价分析法对不同等级邻近建筑物的安全风险进行评估．典型工程实例应用证明提出的方法简便、可行．研究成果对指导青岛后续地铁隧道工程开挖和保证地表建筑物安全有重要参考价值．     

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.     

Environmental risk management for a cross interchange subway station construction in China

Ground surface settlement induced by urban subway construction using shallow tunnelling method is inevitable and it may cause a series of negative impact to existing nearby structures and utilities. In order to guarantee environmental safety, a risk management methodology which aims at process control for ground settlement and existing nearby structures is proposed. It includes 5-stage technology-based steps: survey of existing conditions, designing control standards for key risk factors, analyzing environmental response under tunnel construction and designing process control standards, monitoring and taking proper process control measures during construction, and risk reassessment after construction. This methodology was put into practice in the Huangzhuang subway station construction which is the largest cross interchange subway station construction using shallow tunnelling method in China. According to site survey, nearby pipelines and existing buildings were determined to be the key risk factors. The risk control standards for nearby pipelines and existing buildings were made according to available standards in China and related literatures. Design of process control standards for ground surface settlement was assisted by numerical simulation, which aimed at controlling the key risk factors. During construction, monitoring was adopted for the nearby pipelines, existing buildings and ground surface. After the four drifts excavation of the double-deck part of Line 4, a series of risk control measures, which included treatment of the unfavorable geological bodies, installation of roof pipes, compensation grouting, full-face grouting and some other control measures, were taken. Due to these risk control measures, ground surface settlements, except at two measuring points of Line 4, were successfully controlled under the given process control standards for both Line 4 and Line 10. All the pipelines and buildings were under their normal service state during tunnel construction. The maximum deflection for the 6 pipelines above the station was controlled to be within 2 mm/m and the maximum settlement of all the monitoring points for the pipelines was less than 30 mm. For the four important existing buildings in close vicinity, the maximum deflection was less than 1 mm/m; the maximum settlement value was 6.8 mm and the maximum uplift value was 3.0 mm. The risk control system was shown to be effective in ensuring environment safety, structure safety and construction safety. These safety control methods, the methodology of designing these control standards and the measures taken in the construction can serve as a practical reference for other similar projects.