地质环境与隧道工程的安全(卢耀如).ppt
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1、THE EXPLORATION OF,UNDERGROUND SPACE AND PREVENTION OF GEOLOGICAL,HAZARDS,LU YAORU,LIU QI,Chinese Academy of Geological Sciences,Tongji University,地质环境与隧道工程的安全,卢耀如 院士,刘琦,中国地质科学院,同济大学地下建筑与工程系,地质环境与地下工程的关系,隧道、地铁等地下空间的开拓与地质 环境之间存在着密切的联系,地质环境的特性制约了地下工程的经 济与安全,地下空间的开拓应以地质环境作为规 划、设计与施工的重要基础,主要内容,对影响隧道工程建设
2、的几种地,质环境进行探讨,分析不同地质环境中进行隧道 工程建设可能诱发的工程地质 问题,针对隧道等地下空间的开拓提,出了八点建议,一、中国隧道(隧洞),工程的,历史与现状,History and,Present Situation of tunnel in China,Before 3600 years, the tunnel,system for mining mineral resources had already,reached higher level, which some structural wood system are still remained in Daye, Hub
3、ei province, China.,Ancient tunnel system for mining,copper are still exited in Daye, Hubei,中国具有五千多年的文明历史,对,隧道等地下空间的开拓已有长久的,历史,在湖北的大冶地区,目前仍保留有,三千一百多年前西周时期的开矿巷,道,深度达到地下二十至六十多,米,有四百多座竖井、斜井和上千,条平巷,纵横交错,层层叠压,显,示了开凿隧道的高超技术,井巷结构示意图,湖北大冶铜绿山古代矿井和炉渣分布图,(湖北黄石市博物馆潘红耘、周百灵、周保权 供稿)(卢耀如,1986),中国古代地下隧道的开挖还用于帝王陵墓的,建
4、造,通过修建隧道在战争中用于攻城等。,目前,地下空间的开拓已遍及各个方面。在,水利水电建设方面,大型引水隧洞长的达,41km,大型发电隧洞长度达17km以上,埋,深达2500多m。铁道建设方面,隧道至少长,度在10km以上,已建成的有20多km,拟建,设的还有35km以上的。,中国许多城市正在大力发展地铁建设,城市,地下空间的开拓显示了其多功能性,In ancient China, the,developments of sub-surface were mainly for the purposes related to mining mineral resources, emperor t
5、ombs, war, water conservancy etc.,In present, the multi-,purposes of sub-surface,developments are related to water conservancy and hydropower, railway, expressway, storing,materials, recreation areas ,etc,Urban ground,Expressway network in the suburb and exurb,Surface or underground Parking in the e
6、xurb,Exploration of underground space,transportation network Joined by surface and underground Transportation,Underground,Subway construction,network Underground,business district,recreation areas,Underground green space Human underground living space,The sketch shows the purposes structure,of sub-s
7、urface development,连,远郊及邻 区高速公 路网络,地表或 地下的 郊区汽 车停车 场,地下空间开拓 地下铁道建设,城市地面 交通网 地 表 与 交 地 通 下 网 相 络,地下商业区,地下娱乐区,地 下 绿 地 人类地下生存的地下空间 中国城市地下空间开拓的功能示意图,In long and deep tunnels, the most,important problems are related to geo-,environment and geohazards,二、主要几种地质环境对,隧道工程的影响,SEVERAL MAIN GEO- ENVIRONMENTS TO
8、INFLUENCE TUNNELS,在长、大、深埋的隧道(隧洞) 建设中,遇到的地质环境问题是 多方面的,既影响到工程造价、工期,也危 及隧道的施工与运行期间的安全,1SAND AND GRAVEL,FORMATION,1砂卵石层地基,砂性基岩的稳定问题,STABILITY OF SAND FOUNDATION,砂卵石层为渗流的动水 压力冲刷管涌的分析,LIQUEFACTION AND PIPING HAZARD OF SAND,FOUNDATION IN SUBWAY CONSTRUCTION,It is needed to,point out that the features of th
9、ree phrases flow.,三相流,THREE PHRASES FLOW,0,For the compressed gas mass:,d dt, t,+, V x,x +, y,Vy +, z,+Vz,所以,div V=,- 1 d dt,When the start velocity V0 0 , then the compressed gas mass has a speed trend.,For the un-compressed water and rockmasses:,Vz + z,Vx x,+,Vy y,0,(density)=,d dt,0,div V 0,o,Com
10、pressed gas mass pressure Pa:,Pa a A Pof (Ra,a)dA,(8.34a),,f(Ra,a)dA气团体积变 化函数;Po原始压强;o 原始密度;Pa高压气团压 强;a高压气团的密度。,式中,GE上面覆盖的可能 破坏的岩土体重力;GR库水作 用下可增加荷载重力。所以:, R,a o, A (GE+GR) f (Ra,a)dA,(8.36),产生气爆地震类型时,需要使,产生的气爆剪切破坏力a为:,-,a( a )+Fa CR (8.36),式中,Fa产生诱发地震破裂 岩体的断面面积;CR破坏岩体,的凝聚力。,j=1,By multi-factors to e
11、valuate the earthquake,to be caused by the reservoir,Ce(,n R Ii i=1,m PIi/n+ R Dj PDj/m)/2,(8.37),Es=EwCeKc,式中Ce对比评判系数;RIi间接因素i 项的比值; PIi 间接因素i项的权重;RDJ 直接因素j项的比值;PDJ间接因素j项的权 重;Kc岩溶发育中差异系数;Ew地震条 件方面差异系数;Es预测地震震级。,地 下 水 等 水 位 线 图,成 都 市 第 四 系 潜 水,砂卵石层对隧道工程的危害主要有:,(1)隧道施工排水引起周边沙层的机械管,涌与塌陷;,(2)沙层的溃入诱发大量地
12、下水邻近河,水的溃入;,(3)不同结构的沙层地质,诱发不均匀沉,陷,影响隧道安全;,(4)沙层中夹有大块卵石对盾构施工产生,影响,甚至卡住刀片,The hydrodynamic conditions,of percolating flow in sand and gravel formation are,easily caused the liquefaction and piping, when the tunnels to be digging to through them.,For the higher dynamic,condition and the,liquefaction fe
13、ature of sand,deposit in larger river ,therefore it is not suitable to,construct the tunnel by,immersed tube method.,湍急河道下砂卵石层对隧道安全分析图,长江中,水流湍急。在砂卵石层中开挖槽,建沉管法隧道 砂卵石层不易保持边坡稳定 河流中,砂卵石层易于蠕动使上覆卵石层厚度发生变化 沉管底砂卵石层,易受流速快的砂卵石层中水流的绕流, 而发生潜蚀,使沉管产生不均匀的压应力而破坏,对厚的砂层进行隧道明挖时,需要考虑三 个问题:,(1)抽水初始水位下降诱发潜蚀、冲刷和地,面沉降;,(2)
14、大量抽水后,水位下降缓慢,形成压力 水头H,这时易于诱发下部的大量砂层溃 入;,(3)下部有相对隔水层时,由于上部隧道抽 水降低水压,下部高压水汇合;透水层隆 起,产生向上大量越流补给,危及隧道的运 行,For the sand formation to be digging, the harmful phenomena will appear in three ways:,1. The ground water table may,decrease by pumping to appear the piping;,2. The ground water table will contain,
15、the water head for the much water flow to be pumping in tunnel or foundation pit;,3. By pumping for long time, the lower,confined, sand and gravel aquifer may happen the leakage flow to the bottom of upper tunnel to cause more hazard.,砂层对隧道(深基坑)产生灾变危害分析图,Analysis of the sand formation to harm,the fo
16、undation pit (deep foundation ),A - collapse zone of tunnel roof,B - piping zone in tunnel both sides,C - strong water-sand invasion zone,D - emerging leakage water-sand zone in tunnel bottom,2软土地基,2SOFT CLAY FORMATION,For the higher watery,feature of soft clay, the most important problem is the liq
17、uefaction and creep,deformation to influence the foundation stability.,A tunnel under the lake in soft clay formation, owing to the stones about 20 cm to,influence the shield to cut the soft clay, then the collapse was happened, and the lake water was invaded into the tunnel.,Shield tunneling,Analys
18、is of the water invade induced by,the creep deformation resulted from tunnel driving in soft clay formation,软土基础的,稳定性问题,Stability of soft soil foundation of a tunnel,The larger stone in soft soil to,influence the shield in normal,在滨海相、湖相古地质环境中:,沉积的软土多处于相对运动缓慢,或相对停滞的水环境中,颗粒细,孔隙度大,土质软弱,,含水量大,易于产生蠕变,凝聚
19、力很小,基,本上可不计,在这种土层中修建隧道,需要考虑的工程 地质问题有:,(1)土性软弱,经受隧道的荷载易于产生沉,陷,由于厚度变化,产生的不均匀沉陷对 隧道内衬砌等结构造成形变;,(2)由于软土的蠕变也会对隧道的结构产生,影响,及时衬砌和支护都是非常重要的;,(3)软土经常处在地下的还原环境下,微生,物作用等易于产生甲烷气体,这些气体聚 集于软土层空隙中,隧道掘进时易发生有 害气体的溃入,甚至遇到火种后引起爆炸,上海地区软土层中存在甲烷气的,地质剖面图(叶为民等,2001),对于软土,当隧道长度不长时,利用盾构易于 穿越,若隧道穿越软土的长度较长时,由于软土的蠕 变特性,会产生超量切削,于
20、是在隧道盾构掘 进的前方会产生蠕变凹槽,若软土层厚度不太大时,易于诱发上部海水活 河水大量溃入隧道。,盾构穿越软土层,风险是必须要考虑的,For the feature of soft clay,formation, to dig the long tunnel by shield method, the,dangerous trend is to form the depression in the soft clay and to lead the sea water or lake water to harm the tunnel.,软土层掘进隧道产生蠕变凹槽诱发溃水灾害分析图,Othe
21、r ways, the tunnel in soft clay bed, the uneven land subsidence in a very important problems, which may cause the harm to the tunnels.,软土基础的不均匀沉降,(陈基炜和詹龙喜,2000),Uneven land subsidence in soft clay,formation,(Chen Jiwei, Zhan Longxi, 2000),For the long tunnels under the sea water, the activity of fau
22、lt, earthquake, are also needed to study.,海底盾构诱发海水入侵机理分析,For the long tunnels,under the sea water, the activity of fault,earthquake, are also needed to study.,3碳酸盐岩地层,3KARSTIFIED CARBONATE,ROCK FORMATIONS,Resulted by the five pairs of special feactures related to karst water:,五个对立统一特征,1. The isolate
23、d and semi-,isolated water flow and,the unified water table,It has been shown in plenty of information in China that karst water flows in not a few areas not only stand in isolated and semi- isolated situations but also have the same unified ground water table. Both exist in unification under specif
24、ied conditions when the Earths crust is stable; otherwise, they will convert to each other.,Karst water flow under a unified ground water table often converter into,separate water flows due to the uplifting of the earth crust and the undercutting of the river valley. On the contrary, isolated and se
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