【作者】 王凯；

【导师】 康海贵；

【作者基本信息】 大连理工大学 ， 港口海岸及近海工程， 2013， 博士

【摘要】 地铁作为现代化的交通方式,已逐渐成为世界各国解决城市交通拥堵问题的重要举措之一。目前我国已投入运营和正在修(筹)建地铁的城市有20多个,地铁的建设迎来了发展的高潮。地铁隧道工程一般处于城市中心地带,地层中各种管线交错密集、分布复杂,隧道施工必然会对其安全造成不利影响,若控制不力则极易造成煤气泄露爆炸、水管爆裂形成水患、电缆断裂造成停电或通讯中断等安全事故。对于历史较久的埋地管道而言,由于长期埋置地下,受周围环境的侵蚀及多年使用的损害均会造成其力学性能的劣化,特别是处于滨海地区(如大连、青岛),由于海平面上升等自然因素影响导致的海水入侵,造成此区域的地下建筑设施长期受海水浸蚀而发生腐蚀。而这些地区的地质条件又相对复杂,存在“岩质坚硬”和“土质松软”并存、“高地下水位”的地质特点,因而钻爆法成为该类地区地铁隧道的主要施工方法。当采用钻爆法施工时,爆破开挖产生的地震将会对邻近已经发生腐蚀(老化)的埋地管道产生不利影响,加剧腐蚀管道的破裂,造成其周围地层条件恶化,加大地铁施工难度及风险。但目前的研究工作基本上都是针对采用盾构法施工的非岩质地区地铁隧道,并且没有考虑管道腐蚀、老化等不利影响,而关于采用钻爆法施工的地铁隧道对邻近腐蚀管道的影响研究几乎还未开展。因此,开展钻爆法施工对邻近腐蚀管线的影响研究具有重要的现实意义和理论价值。本文以大连地铁隧道工程为背景,在调研工程沿线埋地管道的类型、接头型式、埋设年代和地质条件的基础上,开展管道的室内腐蚀试验及力学性能试验,进而建立管道的腐蚀速率预测模型及剩余强度预测模型。借助现场监测及数值模拟等手段,研究爆破地震波在岩土体的传播规律以及埋地管线在爆破地震波作用下的动力响应。基于ARMA模型对钻爆法施工条件下的浅埋管线变形进行了预测,并结合建立的管线沉降引起的经济损失模型和考虑管道剩余强度的安全控制标准,对地铁隧道施工诱发管道破坏的风险进行评估分析。最后,结合大连地铁隧道钻爆法施工的工程实践,从爆源控制、隧道开挖方式优化以及地震波传播过程控制等角度,提出城市地铁隧道钻爆法施工过程中沿线埋地管线的安全防护控制措施。论文的主要研究工作如下：(1)对海水侵蚀环境下管道腐蚀速率进行了模拟试验研究,研究了两种材质管道的腐蚀速率、腐蚀规律和特性；将灰色理论中的灰关联分析用于分析管道腐蚀影响因素的关联度,然后与BP神经网络相结合,建立了基于灰关联分析的BP神经网络预测模型,对管道的腐蚀速率进行预测,并与实测值进行对比,该模型的预测结果精度较高；使用遗传算法改进BP神经网络,并将改进后的神经网络成功应用于腐蚀管道的剩余强度预测。(2)以采用钻爆法施工的大连地铁一号线千山路站至松江路站区间隧道为工程背景,对该区间地铁沿线的埋地管线进行了变形监测和爆破振动监测,并对监测数据进行分析。根据爆破监测数据,采用回归分析法建立了反映大连地铁隧道爆破地震波传播特性的质点振速萨道夫斯基预测公式。在钻爆法施工过程中,可以参考萨道夫斯基公式并结合现场爆破监测数据来不断地完善和调整爆破参数,从而指导地铁隧道后续阶段的施工。(3)采用FLAC3D软件,建立了隧道-岩土体-腐蚀管道三维数值模型,对钻爆法施工过程进行数值模拟,并将模拟结果与现场爆破监测结果进行对比分析。研究结果表明：数值模拟得到的爆破地震波和地表质点最大振速随爆心距的衰减规律与实测结果一致。说明采用数值模拟研究地铁隧道钻爆法施工产生的爆破振动效应是可行的。根据地表质点振速衰减规律,建立了控制最大段药量的计算公式。最后,采用数值模拟方法研究了不同管道埋深、不同管道腐蚀程度以及不同隧道开挖方式下钻爆法施工引起的爆破振动效应。研究结果表明：深埋管道较浅埋管道爆破响应趋于激烈；由于管道腐蚀导致管道刚度的下降,管道沉降和最大拉应变呈非线性增大；全断面开挖时,围岩应力响应最小。(4)管线的变形受很多因素影响,很难建立一个包括所有影响因素在内的管线变形随时间变化的函数关系式。ARMA模型强调“让数据自己说话”,从数据本身来寻找可以较好描述数据的模式,从而可以保证模型与数据拟合较好。本文基于ARMA模型对大连地铁隧道沿线的浅埋管线变形进行预测,预测数据误差较小,除个别数据有一定误差外,预测数据与原始数据基本重合,表明ARMA模型可以用来预测管线累计沉降。(5)以经济损失为评价指标,提出了钻爆法施工对邻近腐蚀管线影响的风险评估方法。首先建立了考虑管线剩余强度的破坏评价标准,根据模糊数学的有关方法,提出地面沉降控制标准的隶属度函数,并结合管线破坏的经济损失表达式,最终确定了地表最大沉降与经济损失期望值之间的关系。论文还从风险分析的角度研究了大连地铁一号线松江路站至东纬路站区间隧道钻爆法施工对邻近某混凝土上水管的影响。(6)在现场爆破监测、数值模拟及风险评估分析的基础上,结合大连地铁隧道钻爆法施工的工程实践,从爆源控制、隧道开挖方式优化以及地震波传播过程控制等角度,提出了城市地铁隧道钻爆法施工过程中沿线埋地管线的安全防护控制措施,为类似工程的钻爆法施工方案的制订和埋地管线的安全防护提供参考。更多还原

【Abstract】 Subway as a modern transportation has gradually become one of the world an important measure to solve the problem of urban traffic congestion. At present, more than20cities have subway and construction of the subway in China. Subway tunnel engineering general is in the heart of the city, the various pipelines staggered intensive in the formation. Tunnel construction is bound to adversely affect pipelines security. If inadequate control could easily cause a gas leak explosion, water pipes burst formation flooding, cable breakage caused by power failure or breakdown in communications security incidents.For the buried pipeline with a long history, due to the long buried underground, the erosion of the surrounding environment and the years of damage could result in the deterioration of mechanical properties. Especially in the coastal areas (such as Dalian, Qingdao), due to sea level rise and other natural factors cause, the underground construction facilities in this areas are long-term corrosion by seawater immersion. Coupled with relatively complex geological conditions in these areas, therefore, the main construction method of subway tunnel in the region is drilling and blasting method. When construction of the drilling and blasting method, blasting excavation produced ground motion will adversely affect neighboring already buried corrosion pipeline. These will increase the difficulty and risk of the subway construction. The present studies are focused on the non-rock area of subway tunnel constructed by shield method, without considering the adverse effects of pipeline corrosion.The studies for influence of blasting excavation on nearby corroded pipeline has not started yet.Therefore, it has important realistic and theoretical value to study the effects of the blasting construction on the corroded pipeline.This paper takes Dalian subway tunnel as background, based on the investigation of the joint type, planting age and geological conditions of the buried pipeline along the project, carry out the pipeline corrosion testing and mechanical testing. Based on the mechanism of electrochemical corrosion, the corrosion rate prediction model and residual strength prediction model of of pipeline were established. By means of in-situ test and numerical simulation method, the transmission of blasting seismic wave in rock and dynamic response of buried pipelines under blasting seismic wave were studied. The deformation of Dalian subway shallow buried pipelines was predicted by ARMA model. Combined pipeline subsidence caused economic loss model and the consideration of the pipeline residual strength security control standards, the risk of the pipeline deformation induced by tunnel construction was assessed. Finally, according to the practice of blasting excavation of Dalian subway tunnel excavation, the security control measures of buried pipelines during the construction process of blasting excavation were proposed. The main contents are as following:(1) The simulation tests were conducted on the corrosion rate of pipeline in erosion environment. The corrosion rate, corrosion regularity and characteristics of two kinds of pipeline were studied. The grey relational analysis in grey theory was used for the analysis of pipeline corrosion influence factors, and then combined with BP neural network, BP neural network prediction model based on the grey relational analysis theory was established. The corrosion rate of pipeline is predicted, and compared with the measured value; the accuracy of the predicted results of the model is high. Improved BP neural network using genetic algorithm and it is successfully applied to predict of the residual strength of corrosion pipeline.(2) Taking the drilling and blasting construction of Qianshan Road Station to Songjiang Road Station interval tunnel in Dalian Metro Line1as the engineering background, the deformation monitoring and the monitoring of blasting vibration of buried pipeline along the subway were conduct. According to the blasting monitoring data, the prediction formula for blasting seismic wave propagation characteristics of Dalian subway tunnel was established by regression analysis method. Combined with the blasting monitoring data and the prediction formula to continue to improve and adjust the blasting parameters, so as to guide the subsequent phases of drilling and blasting construction of subway tunnel.(3) Using FLAC3D software, the three-dimensional numerical model of the tunnel-the geotechnical body-corrosion pipeline was built, and the blasting construction process was simulated. Then, the results of numerical simulation and field monitoring are compared and analyzed. The comparisons show that the numerical simulation of the blasting seismic wave and the maximum vibration velocity of ground particles attenuation with distance from the explosion center in agreement with measured results. This indicates that the study of the blasting vibration effect of blasting excavation by using numerical simulation method is feasible. Based on the surface vibration velocity attenuation formula, the calculation formula for controlling maximum dose was presented. According to the peak value of vibration speed different, the relationship curves of distance from the blasting center with the single maximum charge were fitting out. Finally, the blasting vibration effect caused by blasting excavation was simulated with different buried depth of pipe, different corrosion degree of pipeline and different excavation methods. The results show that the blasting response amplitude of deep buried pipeline is greater than shallow buried pipeline. Pipeline corrosion leads to the decline of pipe stiffness, so the settlement and the maximum tensile strain of pipeline increase nonlinearly. There are three tunnel excavation ways:Full-face method, Bench excavation method and Step-by-step excavation method. The stress of surrounding rock is the largest of Full-face method.(4) Pipeline deformation is affected by many factors. It is difficult to establish the function relationship which includes all the factors for pipeline deformation changes with time. ARMA model emphasizes the "let the data speak for themselves", from the data itself to find could describe the data model, which can ensure the model fit the data better. Based on the cumulative settlement data of underground corroded pipeline in tunnel blasting construction process, ARMA model is established. Deformation of buried pipeline along Dalian subway tunnel is predicted. The model has high prediction precision, which can be used to predict the pipeline settlement.(5) The expression for pipeline settlement caused economic losses is first established. Then, the membership functions for Pipelines being damaged and destroyed are introduced. The rigid pipeline damage control standards are presented by considering the pipeline residual strength.Finally, the risk of buried pipeline along Dalian subway tunnel during tis construction was analyzed. According to the statistical data of surface subsidence value in similar projects, the maximum surface settlement probability distribution function value was fitting out. According to the function relationship between economic loss and the surface settlement, the probability distribution curve of pipeline deformation caused by the economic loss was finally obtained.(6) On the basis of blasting monitoring, numerical simulation and risk assessment, combined with the practice of blasting excavation of Dalian subway tunnel excavation, the security control measures of buried pipelines during the construction process of blasting excavation were proposed. These provide references for the security of buried pipelines during the construction of subway tunnel using drilling and blasting method.更多还原