浅议盾构法隧道施工过程中的安全控制措施

近年来盾构法隧道施工逐渐成为城市地下铁道施工的主流方法,其特有的施工安全管理问题也引起了广泛关注。文章结合深圳地铁二期工程2号线2222标侨香站—香蜜站—香梅北站两区间的施工实践,对土压平衡式盾构法隧道施工的安全生产进行了研究,并提出了对城市地铁及地下工程施工的安全控制措施。     

Support Form and Construction Sequence for Soft Rock Tunnels with Small Spacing,High Stress and Deformation北大核心CSCD

Increasingly, stations are being extended to tunnels due to the effects of topography on mountain rail-ways and the requirements of the stations. A forked tail tunnel arrangement is the most popular one, but the concomi-tant effect of the following tunnel on the antecedent tunnel during construction of a tunnel with small spacing causes cracking of the primary support and secondary lining as well as heaving of the invert, which continues to trouble en-gineers. Different problems are encountered by different tunnels because of the complexities and variations of geo-logical environments. Using the construction of two single-line sections with small spacing for the Xinchengzi tunnel on the Lanzhou-Chongqing railway as an example, the support form for a soft rock tunnel with small spacing and high geostress and deformation, as well as the invert construction sequence of the left and right lines and secondary lining, are analyzed and discussed. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Three Dimensional Numerical Simulation Study on the Tensile Test of the Embedded Components in Segment Joints of Deep Buried Storage and Drainage Shield Tunnels北大核心CSCD

The numerical simulation was carried out based on tensile test of the embedded components in segment joints of the deep buried storage and drainage shield-driven tunnel in Shanghai in order to study the numerical approach for mechanical analysis of segment joints of the tunnel. Using the concrete damage plasticity model and nonlinear springs, the 3D refined numerical model was established, in which the embedded components with complex geometries and the bond-slip behaviors between the concrete and bars were taken into consideration. Three kinds of embedded component models with different degrees of refinement were established and simply loaded. By comparing the calculation results and considering the spent time and the accuracy of calculation, the simplified form of the embedded components used in the overall model was determined. Nonlinear springs between anchor bars and concrete were set in the model in order to simulate the bond-slip behavior between them. In addition, two contrast models were also established using binding constraint and face-face contact constraint between concrete and anchor bars respectively. The three types of models were loaded in accordance with the test conditions. Comparing the results of the numerical calculation with the test results, it is shown that the "nonlinear spring model", which takes the bond-slip behavior into consideration, is more consistent with the test results than the "face to face contact model" and "binding model". And the model also reflects the failure mode very well. It indicates that the three dimensional refined modeling method used in this paper is applicable for similar tensile tests. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Key Techniques for Lean Construction Management of the High Speed Railway Tunnels北大核心CSCD

Improvements of management mode and application level of informationization techniques are the key factors to safe and efficient construction of the high-speed railway tunnels considering the complexity and diversity of construction techniques, unpredictable risk factors and varied geological conditions. In the paper it proposed a management mode for lean construction of high-speed railway tunnels, studied the in-depth integration and applica⁃ tion of key technologies of BIM, advance geological prediction, tunnel surrounding rock measurement, 3D laser scan⁃ ning, etc. in the lean construction management of high-speed railway tunnels, and developed the light portal APP and cloud-based information management system. Through the verification of practical engineering application, it re⁃ alized good monitoring of key risk resources in tunnel construction, redline control for key tasks and effective manage⁃ ment of safety and quality, increased efficiency of collaborative operation of all parties involved and reached the goal of lean construction and management. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

那吉航运枢纽工程左岸岸坡塌方原因及处理方案

分析那吉航运枢纽工程上游左岸边坡运行期出现不同程度塌方的原因,认为在涉水岸坡设计中应重视坡脚土体的稳定性、地下水位骤降,以及水流波浪对岸坡的冲刷和吸附作用。对塌岸段提出放缓边坡和水泥搅拌桩加固土体两个处理方案,通过对其在安全、施工、工程投资、工程影响等方面比较推荐了放缓边坡处理方案。     

某轨道交通1号线雅蛮区间隧道岩溶突泥突水处治对策分析

以某轨道交通1号线雅蛮区间左线ZDK19+200处开挖支护施工时发生突水突泥事件为工程背景,分析了岩溶突泥突水的成因,完成对溶洞淤泥清理、一次涌泥处理、二次涌泥处理以及掌子面加固等措施;对右线地质进行补勘,提前处理隐藏的岩溶,对突泥突水引发的周边构造物裂缝和沉降问题进行加固处理;在此基础上,结合本次工程事故与前人对岩溶隧道的研究,对处理溶岩突泥突水问题提出可行性建议。     

重载铁路隧道穿越富水砂层综合施工技术研究

重载铁路隧道长段落穿越第三系富水砂层,隧道开挖后,在地下水渗流作用下,富水砂层颗粒随水流失、粉质黏土含水率增大,诱发掌子面砂层、粉质黏土等变形失稳,局部甚至发生涌砂、突泥、突水现象,严重影响施工进度。为此,根据地层性质及成因分析,采用理论与现场试验相结合的动态设计,确保施工安全。设计中采用了对围岩超前预注浆加固封堵地下水、掌子面玻纤锚杆注浆提高核心土的整体稳定性,拱部超前大管棚预支护控制围岩变形,长导管泄水降压降低周边砂层的含水量,施工过程"快挖、快支、快封闭"的原则,从而实现安全开挖,快速通过的处理方案,可为类似工程提供借鉴。     

大跨度隧道塌方处理技术

研究目的：大跨度隧道洞口地形地质情况复杂，围岩完整性差，易出现塌方，对隧道施工进度和质量影响较大，本文结合大丽线禾洛山隧道出口段塌方的处理，对复杂地形地质情况下大跨度隧道洞口段的施工进行总结。 研究方法：针对禾洛山隧道出口段的地形、地质条件以及塌方情况，采用工程类比、数据分析和优化方案的方法，确定经济合理的处理措施，并对围岩、结构变形等进行了量测和分析，对主要结构进行了必要的检算。 研究结果：针对禾洛山隧道出口段具体的地形、地质以及塌方情况，采取有效的处理措施，取得了良好的效果。 研究结论：大跨度隧道洞口段地形、地质情况复杂，围岩软弱，有效预防和处理隧道塌方，顺利通过洞口段是隧道施工成败的关键。本工程采用大管栅、小导管注浆联合超前支付、预留核心土开挖塌体的处理方法，使塌方得到了有效控制和处理，保证了安全顺利通过塌方段，解决了隧道施工进洞难的问题。     

隧道衬砌病害探地雷达三维正演模拟及工程验证

从Maxwell旋度方程出发,通过引入复介电常数和复磁导率,推导导电介质UPML吸收边界在考虑和不考虑磁损耗情况下各区的电场和磁场分量的时域差分公式。通过选取各区不同的匹配参数,建立模型区与UPML吸收边界电场和磁场分量的统一离散差分公式。用MATLAB语言编制基于UPML吸收边界的图像可视化的探地雷达三维正演模拟程序。正演模拟衬砌内方形空洞三维地电模型,揭示方形空洞在不同显示剖面上的图谱特征。单剖面的响应特征类似"平锅盖形",z方向切片图定出空洞的形状;反射界面呈强负相反射异常,在立体剖视图中,空洞角点位置产生了2个交叉的双曲线绕射波。将该方法应用于现场隧道衬砌质量的检测,并开孔验证。结果表明:不密实区反射界面多且不规则,同相轴错断、零乱、不连续的较强反射能量团块状异常;在z方向切片图上能清楚反映隧道衬砌密实程度,并且判译直观、准确。     

盾构法地铁隧道施工引起的地表变形分析

以南京地铁1号线许府巷—南京站区间隧道为背景,结合现场监测数据及各项掘进参数设置,对土压平衡盾构在富水饱和粉土、粉砂夹细砂、粉细砂地层中掘进引起的地表变形过程和分布规律进行分析,并使用有限差分法程序FLAC3D对考虑盾构施工工序、地下水位、土仓压力和注浆等因素的地表变形进行模拟计算分析。实测分析结果表明地表变形特征为:沉降速率大,测点最大沉降速率在-12~-15 mm.d-1之间;地层稳定快,盾尾脱出2~3 d后地层即趋于稳定;影响范围小,盾构掘进对隧道纵向地表的扰动在刀盘前方约10 m至盾尾后方16~20 m的范围内,横向地表沉降主要分布在隧道中心线两侧各5~7 m的范围内,地表距中心线20 m以外几乎不受影响。模拟计算地表沉降分布结果与实测数据基本吻合。