超大直径泥水盾构接收关键技术

以南京纬三路过江通道工程N线盾构接收施工为例,介绍软土地层超大直径盾构接收施工工艺。提出一种新型的盾构接收洞门密封结构形式,采用弹簧钢板束结构代替传统密封结构,避免了常规洞门密封结构易损坏、操作不便的缺点;设计制作用于加强洞门封堵注浆的特殊管片,实现了良好的洞门封堵效果,可为今后类似工程提供一定借鉴。     

喷射混凝土液体速凝剂研究现状

概述了国内外液体速凝剂的发展现状,按主要促凝组分把液体速凝剂分为4大类:水玻璃型、铝酸钠(钾)型、硫酸铝型和无硫无碱型液体速凝剂,针对每类液体速凝剂,分别从制备、性能特点和促凝机制研究3个方面对其国内外研究进展和最新成果进行了阐述。指出目前液体速凝剂尤其是无碱液体速凝剂在掺量、价格、储存稳定性和安全环保等几个方面存在的问题,并提出了今后液体速凝剂研究方向。     

某新建地铁车站与既有站换乘模式及换乘设施研究

为实现合理换乘的目标,以既有2层单柱车站与新建3层双柱车站换乘为研究对象,采用理论分析和仿真模拟相结合的方法对换乘模式进行分析。然后,基于预测客流对换乘方案进行仿真模拟分析,得出结论:1)不同的客流量应选择不同的换乘方式,客流量较大时,应采用单循环的换乘方式,新建车站站台纵向可均匀布置4组宽1.2 m的上下行扶梯和宽1.4 m的备用楼梯,并在既有站底板沿中柱对称破除2 m宽的孔洞,设置台台换乘通道,可满足远期客流换乘和疏散的需求;2)通道(楼梯)的通行能力随着通道(楼梯)宽度的增加而增大,但增大趋势逐渐减小,在客流较大时应设置导向措施引导乘客适当使用楼梯或采取限流措施;3)对于"L"型换乘车站,"一顺"布置时换乘更便捷,而"双八字"布置更能缓冲客流,因此,需根据具体客流情况选择相应的换乘方式;4)近远期车站不同期建设时,应考虑换乘需求并为后续线路预留实现换乘的工程条件。     

Study of Engineering Geological Conditions and Railway Tunnel Scheme across Qiongzhou Strait（琼州海峡工程地质条件及铁路隧道方案研究）

The cross sea channel for the Qiongzhou Strait not only provides a solution for transportation, but also plays an important role in the political and economic development of the region. In addition, the project has an extensive impact on many fields, such as energy, national defense, science and technology, opening up and reform, comprehensive utilization and so on. It is a significant project to enhance China′s comprehensive national strength, defend the country′s territorial integrity and promote regional economic development. The geological conditions across the Qiongzhou Strait are complex. A large amount of existing engineering geological information and hydrogeological data are collected, based on which the seismic impact on subsea tunnels and the main geological conditions including tectonic structures are analyzed. Different options crossing the Qiongzhou Strait have been considered and compared in terms of engineering geology, environmental condition, as well as the construction feasibility. The analystical results indicate that a subsea tunnel has more advantages over a bridge. Because more complicated technical difficulties have to be solved for a highway tunnel which would potentially increase construction and operation costs, a railway tunnel scheme is recommended. Vehicles can be carried by trains through the Qiongzhou Strait railway tunnel. Based on the seabed topography and geological conditions, four preliminary railway tunnel routes are proposed. After a comprehensive comparative analysis, the railway tunnel route Ⅱ is identified to be superior to other alternatives and should be the basis for determining the final tunnel layout. The proposed tunnel cross section includes two railway tunnels and one service tunnel. All the three tunnels have the same structural form and dimension and will be constructed by shield.     

Design Method and Application of Rock and Support System for Super large Span Tunnel（超大跨度隧道围岩支护体系构件化设计方法及其应用研究）

In order to guarantee the stability of surrounding rock and support structure of super large span tunnel and realize quantification of support structure design, the optimal excavation contour line shape is obtained based on study of influence of initial ground stress on bearing arch of surrounding rock; a new quantitative design method, in which the surrounding rock is regarded as an arch structure, bolts, cables, shotcrete and lining are designed to satisfy the intensity, rigidity and stability of the arch structure, is presented to design the support structure system. The method has been successfully applied to super large span tunnel of Badaling Great Wall Station on Beijing Zhangjiajie High speed Railway; and the applicable results show that the maximum accumulative settlement of crown top of large span section is only 17.3 mm, and the relative subsidence of crown top is only 0.09%, which can meet safety requirements.     

地铁列车振动荷载作用下隧道底部土层孔隙水压力及变形特性研究

为研究地铁列车振动荷载长期作用下隧道底部土层的孔隙水压力及变形特性,以北京地铁7号线2期（东延）工程为背景,利用ADINA有限元计算平台建立典型隧道区间断面的有效应力分析模型,进行上限速度行车荷载作用下饱和场地土层-隧道体系水土耦合动力响应分析,研究典型位置处孔隙水压力时程变化规律,并预测地铁振动荷载作用下引起的沉降量。同时,对北京地铁7号线粉细砂进行土工室内试验,进一步研究隧道底部土层在地铁行车荷载作用下的孔隙水压力及竖向变形发展规律。结果表明： 1）在长期列车振动荷载作用下,隧道底部土层孔隙水压力逐渐增大,且增大值随土层深度的增加而减小; 2）土体的累积超孔隙水压力比和累积应变量随着荷载幅值的增加而增大; 3）与非均等固结条件相比,均等固结条件下的超孔隙水压力比较大,但累计应变量小; 4）列车振动引起的超孔隙水压力和应变均较小,超孔隙水压力在列车停运期间足以消散完毕。     

高地应力深埋层状围岩隧道非对称变形受力机制研究

为深入研究高地应力层状围岩中隧道和支护结构的非对称变形受力特性和机制,以绵茂公路篮家岩隧道为工程背景,采用现场监测和数值模拟相结合的方法,研究不同层理角度和地应力方向下隧道变形、钢拱架应力以及二次衬砌弯矩和轴力的变化规律。结果表明： 1）层状围岩中隧道结构受力的最不利位置常出现在层理面法向方向; 2）隧道的非对称变形机制在于地应力对层理面产生的法向挤压作用和切向滑移作用,当层理面角度缓倾时,隧道拱顶和拱底承受较大挤出变形,当层理面角度陡倾时,地应力方向与层理面夹角越小,隧道衬砌在主应力作用位置产生的滑移变形越大。最后,根据层状围岩隧道变形和衬砌受力特征,提出合理的支护优化措施。     

海底岩溶盾构隧道勘察、设计及岩溶处理关键技术研究——以大连地铁5号线火梭区间海底隧道为例

海底岩溶隧道勘察、设计难度大,施工风险高。以大连市地铁5号线海底岩溶大直径盾构隧道为研究对象,首次采用“跨孔CT物探+钻探”的海底隧道岩溶勘察方案,通过有限元计算确定海底岩溶隧道加固范围,通过抗浮计算确定岩溶隧道基底加固标准,提出海底岩溶的海面预处理具体实施方案和盾构针对性设计方案,从而形成一整套海底岩溶盾构隧道勘察、设计及岩溶处理方案。     

新建地铁站基坑临近及无覆土下穿运营地铁站安全技术措施研究

为研究不同工法零距离施工对既有站的影响,提出切实可行的控制措施,以南京地铁上海路站换乘站为例,介绍新建地铁站（5号线）与运营地铁站（2号线）呈十字换乘情况下,对新建地铁站施作临近基坑及采用无覆土下穿运营地铁站技术的风险管控措施进行研究。提出： 1）通过增设隔离桩,在既有车站两侧形成2个完整基坑,基坑施工可确保既有站运营和结构安全; 2）对换乘节点暗挖段,通过釆用10步分导洞开挖、无覆土完整支护体系,可有效控制运营车站下沉,确保运营安全。     

厦门过海隧道超前帷幕注浆方案优化研究

为了解决过海隧道建设过程中安全快速穿越不良地质段的问题,依托厦门地铁3号线本岛至翔安过海隧道工程,针对其不均匀软弱围岩,对超前帷幕注浆方案进行研究。针对原“99孔-25 m”设计方案存在施工效率低下的问题,通过采取以“减少钻孔、配套优化”为主的系列优化措施,确定“56孔-25 m分段前进式”超前帷幕注浆方案： 1）径向加固范围为工作面及开挖轮廓线外5 m; 2）纵向加固范围为25 m; 3）浆液扩散半径为1.5 m; 4）注浆终孔间距为2.2 m; 5）使用普通硅酸盐水泥单液浆、超细水泥－水玻璃双液浆2种注浆材料; 6）注浆终压为0.5~1.5 MPa。结果表明： 方案优化后的扫孔效率提升至200 m/d以上,注浆效率提高3倍以上,综合施工速度平均达到1.72 m/d,为原计划的2倍,证明了优化方案的合理性和有效性。