盾构近距离穿越施工对已运营隧道的扰动影响分析   总被引：18，自引：2，他引：18  

邵华  张子新 《岩土力学》2004,25(Z2):545-549

基于盾构施工对周围土体及构筑物的扰动影响机理,通过实测数据对盾构近距离穿越扰动影响问题进行了定量分析,并讨论了运营隧道对各盾构施工参数的敏感性.研究结果表明盾构穿越对已建地铁隧道的扰动影响主要以隧道的竖向位移为主.随着盾构推进,隧道结构纵向上呈波浪状,其隆起峰值不断沿推进方向移动.盾尾后隧道段受盾构穿越的影响显著,但隆起峰值始终位于盾尾后.  相似文献   

A Physical and Numerical Investigation on the Stability of Shallow Tunnels in Strain Softening Media   总被引：11，自引：0，他引：11  

D. Sterpi  A. Cividini 《Rock Mechanics and Rock Engineering》2004,37(4):277-298

Summary The behaviour up to failure of shallow underground openings is discussed on the basis of some laboratory, small-scale model tests and of finite element simulation. The experimental results are first illustrated. They were obtained from two-dimensional (plane strain) and three-dimensional tunnel models tested under standard gravity conditions. Then, the phenomenon of strain localisation that characterizes the medium surrounding the model tunnels is discussed, recalling two alternative approaches for its numerical interpretation. On this basis, a finite element procedure for strain softening analyses is outlined and applied to the simulation of the tests in both two- and three-dimensional conditions. The comparison between experimental and numerical results leads to some conclusions on the influence of strain localisation on the overall behaviour of shallow tunnels and on the stability of their headings.  相似文献   

Effects of temperature and humidity upon the transport of sedimentary particles by wind   总被引：3，自引：0，他引：3  

Cheryl McKenna Neuman 《Sedimentology》2004,51(1):1-17

Wind tunnel simulations of aeolian transport carried out over a range in mean temperature between 32 °C and ?9 °C suggest that cold airflows support higher mass transport rates (Q) than very warm air. The magnitude of this increase is larger than expected, so that analytical and semi‐empirical models underestimate Q. Extrapolation of the results suggests that, at ?40 °C, as for example in the dry valleys of Antarctica in winter, Q may be as much as 70% higher than for the equivalent wind speed in hot deserts at air temperatures of 40 °C. Temperature‐dependent changes in air density and turbulence contribute to this result. The decreased tension of water adsorbed onto particle surfaces at low temperatures is postulated to reduce interparticle cohesion and, thus, to increase the elasticity of particle impacts on cold beds. Definition of the roles that temperature and humidity play in aeolian transport is relevant to studies of palaeoenvironmental reconstruction and extraterrestrial (or planetary) geology. Investigation of present‐day, cold climate features and of climate change effects also requires knowledge of these fundamental relations.  相似文献   

Studies on wind environment around high buildings in urban areas     

LIU Huizhi  JIANG Yujun  LIANG Bin  ZHU Fengrong  ZHANG Boyin  SANG Jianguo 《中国科学D辑(英文版)》2005,48(Z2)

High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in Beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings.  相似文献   

云南省祥(云)-临(沧)公路红土坡隧道变形原因及加固方案     

邓星理  张翔杰 《中国地质灾害与防治学报》2005,16(2):74-79

云南省祥(云)-临(沧)公路红土坡隧道，在施工过程中变形严重，洞内数次冒顶、产生地面陷落，并诱发滑坡，严重影响了施工进度并造成较大经济损失。文章根据现场勘查及变形监控量测资料，详细论述了隧道变形特点，从地层岩性、构造、地应力条件、地下水作用、施工工艺、滑坡影响等方面综合分析了隧道变形原因。红土坡隧道变形是软弱的地层岩性、地应力条件改变、地下水作用、施工工艺以及滑坡偏压等各种因素共同作用的结果。且隧道变形诱发滑坡，滑坡又促使隧道进一步变形。基于此，文章提出了首先对滑坡进行支挡，再对隧道围岩进行加固的整治思路，并提出具体工程方案。整治工程实施后，红土坡隧道变形已得到完全控制，取得良好的治理效果。  相似文献   

浅埋暗挖技术在南平市天台隧道工程施工中的应用          下载免费PDF全文

李耀卿 《探矿工程》2005,32(12):56-58

主要介绍了在Ⅱ、Ⅲ类围岩中施工城市浅埋隧道的施工技术，以“短开挖、快封闭、强支护、勤量测”为指导，将隧道分成上、下两个台阶进行开挖，及时进行初期支护，保证施工始终处于安全状态。  相似文献   

浙江江山石鼓水库除险加固工程技术措施          下载免费PDF全文

龚新晖  郐开富  刘席军 《探矿工程》2005,32(4):31-34

根据浙江江山石鼓水库大坝的结构构造特点、水库地质条件以及水库病险原因与状况，制定出一套科学完善的病险水库除险加固工程技术措施和施工操作规程，对病险水库进行了全面彻底治理，并取得良好效果。详细介绍了工程病险状况，除险加固方案设计，施工工艺及操作规程，加固效果检测及评价等。  相似文献   

Stability analysis of tunnels driven in jointed rocks by means of a homogenized limit analysis approach     

Samir Maghous  José E. B. Winiawer  Vanessa F. Pasa Dutra 《国际地质力学数值与分析法杂志》2014,38(18):2009-2032

Conceived as a potential alternative to the classical design methods employed for analyzing the stability of underground structures driven in jointed rocks, the homogenization approach stems from the heuristic idea that, from a macroscopic point of view, a rock mass cut by a network of joints may be perceived as a homogenized continuum. The strength properties of the latter can be theoretically obtained from the failure conditions of its individual constituents: rock matrix and joint interfaces. At the material level, the limit analysis reasoning is used in the context of homogenization to formulate the homogenized strength criterion of a jointed rock mass in the particular situation of a single set of parallel joints. As it could be expected, the obtained closed‐form expressions show the strength anisotropy induced by joint preferential orientation. The support functions (π functions) associated with the homogenized strength criterion are also determined in both plane strain and three‐dimensional cases. This criterion is then applied to the investigation of stability analysis of a tunnel excavated in a jointed rock mass. Upper bounds estimated of the stability factor are derived from the implementation of the kinematic approach directly on the homogenized underground structure. Finally, the approach is applied to analyze and discuss the collapse of the Pinheiros subway station (São Paulo, Brazil). Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

A new numerical approach to the hyperstatic reaction method for segmental tunnel linings     

Ngoc Anh Do  Daniel Dias  Pierpaolo Oreste  Irini Djeran‐Maigre 《国际地质力学数值与分析法杂志》2014,38(15):1617-1632

This paper proposes a numerical approach to the hyperstatic reaction method (HRM) for the analysis of segmental tunnel linings. The influence of segmental joints has been considered directly using a fixity ratio that is determined on the basis of the rotational stiffness. The parameters necessary for the calculation are presented. A specific implementation has been developed using a FEM framework. This code is able to consider the three‐dimensional (3D) effect of segment joints in successive rings on the tunnel lining behaviour. The present HRM allows one to take an arbitrary distribution of segment joints along the tunnel boundary into consideration. In addition, the rotational stiffness of segment joints has been simulated using nonlinear behaviour, as it is closer to the true behaviour of a joint than linear or bilinear behaviour. The numerical results of three hypotheses on ring interaction, which allow the 3D effect of a segmental tunnel lining to be taken into account, have been compared with data obtained from the shield‐driven tunnel of the Bologna–Florence high‐speed railway line project. The numerical results presented in the paper show that the proposed HRM can be used to effectively estimate the behaviour of a segmental tunnel lining. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Impacts of confining pressure and safety thickness on water and mud inrush in weathered granite     

Jinquan Liu  Weizhong Chen  Zhiping Deng  Taogen Liu 《Marine Georesources & Geotechnology》2020,38(2):144-153

Abstract

Due to the strong disintegration and water erosion of completely weathered granite, water and mud inrush disasters are apt to take place in this zone during underwater tunnel construction. The pore, compactness, seepage path length, fracture geometries and their interconnections for water and mud transfer are strongly influenced by confining pressure and waterproof-resistant slab safety thickness. In order to inspect the influence, a series of experiments based on a self-designed testing system and non-Darcy testing method were performed. The results indicated that the water and mud inrush evolution increased with the increase of confining pressure and decreased with the increase of safety thickness. In particular, the confining pressure mainly influences the initial evolution stage, and a critical safety thickness to prevent water and mud inrush is obtained. Besides, the non-Darcy testing method results shows that the water and mud inrush evolution affects the influence of non-Darcy flow. For example, while the safety thickness was smaller than the critical value, the evolution was large and unstable and its behavior transferred into nonlinear. In this case, the flow changed to non-Darcy flow.  相似文献