黏土中盾构开挖面变形与破坏数值模拟研究     

秦建设  虞兴福  钟小春  朱伟 《岩土力学》2007,28(Z1):511-515

开挖面支护应力的控制是土压平衡式盾构施工成功的关键。利用能够考虑大变形破坏的拉格朗日有限差分计算程序,对土压平衡式盾构在黏土地层施工中,因开挖面支护压力控制不当引起的开挖面的变形及破坏问题进行计算分析,探讨了开挖面变形及破坏模式,分析了开挖引起的周围土体应力释放问题,为黏土地层中盾构开挖面控制压力的确定提供参考。  相似文献   

土压平衡盾构施工的顶进推力模型试验研究   总被引：9，自引：0，他引：9  

朱合华  徐前卫  廖少明  于宁  傅德明  吴祥松 《岩土力学》2007,28(8):1587-1594

在盾构的掘削过程中,千斤顶顶进推力是一个重要的施工参数,它不仅决定着施工速度,而且还影响着刀盘的切削扭矩、转动速度等其他参量。但是,目前对千斤顶顶进推力的变化规律,尤其是土体与盾壳之间摩擦阻力的研究还不够深入。以上海地区粉砂地层为参照原型,借助于模型试验方法,通过对盾构机工作参数和地层特性参数进行不同的组合试验,研究了土压平衡盾构推进过程中顶进推力变化的规律,以及土体与盾壳之间摩擦作用的机理及其影响因素。在此基础上推导了盾构千斤顶顶进推力的计算公式。  相似文献   

双圆盾构隧道施工中压重纠偏效果分析   总被引：1，自引：0，他引：1  

蔡丰锡  沈水龙  张兆逵  白廷辉 《岩土力学》2007,28(8):1691-1694

在双圆盾构隧道施工过程中双圆盾构往往会由于以下因素发生侧向偏转：（1）土层分布不均匀;（2）盾构机的制造误差;（3）运输台车的牵引力的不同;（4）已拼装管片的作用;（5）注浆的流失;（6）施工中的不当操作。首先,分析了双圆盾构施工中产生偏转的原因以及纠偏方法,其中单侧压重是纠正双圆盾构侧向偏转的最为简单经济有效的方法。在工程实践中,压重荷载的大小一般取决于操作人员的经验和现场观测偏转角的变化。在单侧压重实施前没有预测其纠偏效果的方法,而且,压重纠偏还会引起周围地层的变位。应用有限元数值模拟的方法,分析总结了压重荷载与偏转角的关系以及双圆盾构周围土层的变形。对于最大允许偏转角为0.6°时,需加压重荷载为350 kN将其纠正。同时,纠偏0.6°偏转角会造成85 mm的额外地表沉降,其结果可供实际工程的施工管理参考。  相似文献   

上海软土盾构法隧道管片厚度的优化     

黄钟晖  廖少明  刘国彬 《岩土力学》2000,21(4):326-330

讲座了盾构法隧道管片厚度大小对其本身内力变形以及接头转角等受力性能的影响;针对上海地铁某区间隧道所取用的管片厚度,从强度、抗裂、防水、耐久性等几个方面探讨了减薄现有管片厚度的可能性。  相似文献   

盾构法隧道的纵向沉降问题   总被引：1，自引：0，他引：1  

胡坚  王军 《上海国土资源》2000,(3):13-18

盾构法隧道纵向沉降问题,包括施工阶段和长期运营中的不均匀沉降问题忆日益引起介关注,本文对其的产生原因,预防措施及工程对微进行了阐述和讨论。  相似文献   

Peck公式在天津隧道盾构施工地面沉降预测中的适用性分析   总被引：3，自引：0，他引：3  

潘海泽  蒋冰玉  黄涛 《测绘科学》2010,35(3):53-55

本文根据天津市区至滨海新区快速轨道交通工程中山门西段SZm标段盾构区间工程的实际观测数据,确定了适用于天津地区的Peck公式以及纵向沉降的指数公式的参数取值范围,并利用确定参数后的公式对地面沉降进行了预测和实际的沉降观测,对比结果显示,参数的确定基本准确,经过修正后的公式可以用于天津地铁施工的地面沉降的预测。  相似文献   

浅析盾构姿态控制的原理和方法     

陈纪东 《现代测绘》2012,35(2):49-52

本文介绍了盾构法隧道施工过程中通过测定固定在盾构上的棱镜坐标推算盾构的位置及姿态参数的原理和方法.  相似文献   

弱电机房防雷系统可靠性关键参数解析     

廖必军  高萍 《气象科技》2012,40(1):141-143

在弱电机房防雷系统建设和工程验收过程中,需要一个全面、实用和直观的评判方法,来评价其防雷系统的防护能力是否达到设备安全的要求。以一个弱电机房防雷工程项目为例,分析并得出影响弱电机房防雷系统可靠性的关键参数是:空间屏蔽效能、传输线缆的屏蔽效能、终端最大脉冲电压设限、机房布线最大开口环的感应电压、均压和泄流能力等。在此基础上,以归纳描述或量化分析的方法,对这些关键参数进行了评估和计算,并得出弱电机房防雷设施效能判定参数表。  相似文献   

Episodic fluid migration in the Fennoscandian Shield recorded by stable isotopes, rare earth elements and fluid inclusions in fracture minerals at Forsmark, Sweden     

Bjrn Sandstrm  Eva-Lena Tullborg 《Chemical Geology》2009,266(3-4):135-151

Drilling through the Palaeoproterozoic bedrock at Forsmark, central Sweden, during the site investigation for a potential geological repository of highly radioactive nuclear waste has provided high quality drill-core material from the upper 1 km of the Fennoscandian Shield. Analyses of stable isotopes (δ¹³C, δ¹⁸O, δ³⁴S, ⁸⁷Sr/⁸⁶Sr), rare earth elements and fluid inclusions in fracture filling calcite and pyrite from these drill cores have resulted in the discrimination of several episodes of fracture mineralisations. These events represent migration of fluids during a wide range of conditions, ranging from high-temperature hydrothermal to present-day groundwater circulation. Four major events have been distinguished: 1) Precipitation of epidote, chlorite and quartz under hydrothermal conditions (T > 150–200 °C) during the Proterozoic, sometime between 1.8 and 1.1 Ga. 2) Hydrothermal circulation at temperatures close to 200 °C with precipitation of adularia, albite, prehnite, laumontite, calcite and chlorite. Most of these minerals precipitated during a tectonothermal event between 1.1 and 1.0 Ga, possibly in response to far-field effects of the Sveconorwegian orogeny. 3) Precipitation of mainly quartz, calcite, pyrite and asphaltite occurred during the Palaeozoic, at temperatures between 60 and 190 °C (mainly at < 100 °C). Mixing of a fluid emanating from an organic rich overlying sedimentary cover and a deep basinal fluid from the crystalline bedrock is suggested to have caused this precipitation, possibly as a far-field response to the Caledonian orogeny and/or the development of the Caledonian foreland basin. 4) The youngest generation of fracture minerals is associated with formation of clay minerals and calcite with minor occurrences of pyrite and goethite. These minerals have probably precipitated episodically during a long time period (possibly from the Late Palaeozoic to the present) from various fluids at low temperature conditions (< 50 °C). Few calcites in equilibrium with the present groundwater suggest that the ongoing precipitation of calcite is very limited.  相似文献   

New data on the structure of the Sea of Okhotsk bottom     

V. L. Lomtev  V. N. Patrikeev  M. G. Gurinov 《Russian Journal of Pacific Geology》2009,3(3):201-209

The reinterpretation of the time and deep sections along CDP Profile 1632 revealed different previously unknown structural features: (1) a buried bar and a Late Pliocene regional unconformity, the Bol’sheretsk and Lebed subaerial shield volcanoes, and the Koni-P’yagina and Magadan megadikes at its level; (2) morphological evidence for the nappe structure of the Okhotsk Arch (homoclinal thrust slices of the acoustic basement with ramp half-grabens in the frontal part and a pull-apart zone with a solitary diapir in the Kol’skii Trough, which divides the arch into two allochthonous megablocks with opposite vergence of their thrusts), which is related to a divergent sheet decollement, probably, at the M discontinuity.  相似文献