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1.
介绍了双江口水电站环境边坡的主要问题是孤石、孤石群、危石、危岩体,通过对它们的发育特征进行分析研究,对其进行了稳定性分类,并综合考虑地形地貌、地质、施工等条件,提出了具体的防治措施.  相似文献   

2.
杜发 《甘肃地质》2022,(2):70-76
孤石在我国南方花岗岩地区普遍存在,其发育无规律性,埋藏及分布较为随机;城市地铁盾构施工孤石探测是公认的技术难题。以福州滨海快线(机场—大鹤站)区间孤石分布区为研究区开展了微动、等值反磁通瞬变电磁、高密度电法、探地雷达探测方法综合勘察试验,从抗干扰能力、施工效率和探测效果方面进行了对比分析,发现因浅表存在高阻砂层屏蔽,高密度电法在15 m以浅具有较高勘察精度、受地下线网影响明显,探地雷达在砂层中的有效勘察深度仅4 ~ 5 m;优选出对于孤石体精细探测的物探方法,“微动 + 等值反磁通瞬变电磁”的组合方法具有抗干扰、较好探测效果,与钻孔验证结果吻合。  相似文献   

3.
福州地铁1号线全线为地下建设,地铁路线主体车站与区间隧道工程均在巨厚淤泥层、富水砂层和花岗岩残积土层等地层中施工,通过研究福州地区特有的工程地质、水文地质等条件综合分析,认为盾构机在软硬不均地层、孤石地层,断裂带、富水砂层中穿越是隧道施工的主要风险源。根据地层的不同工程特性分析了在施工中可能引发的风险事故,同时提出了与之对应的风险措施。  相似文献   

4.
球状或块状花岗岩不均匀风化残留的风化核(俗称"孤石")在我国南方沿海城市普遍发育。"孤石"经常导致盾构刀盘卡住及损坏,且可能引起地表的隆起等问题,因此在盾构施工前对"孤石"进行探测便于提前处理,是地铁工程勘察的难题。孤石与周围土层波阻抗不同的特点为地震映像法在孤石勘探中的应用提供了理论依据。本文首先介绍三维地震映像法的基本工作原理及方法;其次,建立含有孤石的三维地层模型,模拟三维地层中的地震映像法试验,研究不同位置测线的波形剖面图规律,结果表明:当测线在孤石投影区域内的时候,会产生明显的反射波和绕射波,可清晰观察到孤石的存在,经过数据处理后可确定孤石平面性状及埋深;最后,利用该方法对厦门地铁盾构区间的孤石进行勘探,当发现波形异常,揭示反射频率明显变低、振幅增强、有震荡现象和类似于短弧形的同相轴时,可判断为地下孤石。通过对比勘探结果与钻孔资料,验证了该方法的可靠性。本文提出了地铁孤石的探测及三维成像方法,供类似地区进行地质勘探借鉴。  相似文献   

5.
煤层顶板导水裂缝带发育高度是煤矿设计部门在留设防、隔水煤柱时必须考虑的一个重要参数,对煤矿水体下采煤、顶板防治水具有重要意义。基于双阳煤矿水文地质补充勘探项目,在8#煤层采空区上方施工两个地面钻孔,采用地面钻孔钻井液漏失量实测法、钻孔电视摄像技术及传统经验公式法相结合的方法,综合确定8#煤层顶板导水裂缝带发育高度为43.7~45.7m,为地质条件相似矿区在合理确定开采上限、留设防(隔)水煤柱等问题提供方法和数据支持。  相似文献   

6.
厦门地区的花岗岩地层中发育了大量的球状风化体(俗称孤石),对地铁工程的建设产生了不利的影响。通过对厦门地铁一号线、二号线进行钻探及室内试验研究,根据揭示的孤石进行统计分析,并分析对地铁工程的影响。研究表明:厦门地区花岗岩孤石埋深主要集中在0~20m之间;89%的孤石厚度不超过4m;近半数孤石分布于强风化层;其饱和抗压强度主要集中在40~45MPa和90~100MPa,天然抗压强度集中在45~50MPa和100~110MPa;地铁施工时孤石可能会导致盾构机损坏和姿态失控。  相似文献   

7.
花岗岩发育地区球状风化体(俗称孤石)的分布直接影响城市轨道交通工程的建设,准确探明花岗岩孤石的空间分布具有重要的现实意义。为了探明地铁建设过程中花岗岩孤石的分布情况,结合深圳地铁11号线某区间孤石探测试验,采用跨孔超高密度电阻率法研究两孔间孤石分布情况,试验数据能较好反映出土层间电阻异常。试验分析结果与现场验证钻孔的对比表明:该物探方法能在一定程度上揭示孤石的空间分布,为进一步针对地铁工程勘察提供了指导,丰富了花岗岩孤石的探测手段。  相似文献   

8.
通过对冲钻孔灌注桩后注浆技术工作机理的分析,探讨后注浆技术设计的主要内容,及施工中应注意的技术问题和关键要点,结合后注浆技术在福州卵砾石层中的应用实例及效果,为后注浆技术更广泛的应用提供借鉴与参考。  相似文献   

9.
江西省九江县城门山矿区补充勘查项目设计钻孔多为超斜孔,钻孔弯曲度要求高,施工难度大。该矿区多个钻孔都面临着纠斜的难题。本文结合矿区深孔ZKJ4-10孔定向纠斜实例,详细介绍了螺杆钻定向纠斜技术的工作原理、配套设备、操作方法及注意事项。通过矿区钻孔纠斜效果,总结了该技术的优点及不足,为今后地质深孔定向纠斜施工提供了借鉴。  相似文献   

10.
深圳地区花岗岩球状风化体地下分布规律统计分析   总被引:1,自引:0,他引:1       下载免费PDF全文
深圳花岗岩发育地区球状风化体(俗称孤石)广泛分布,对地下工程建设产生了不利的影响.通过对深圳地区花岗岩孤石大样本的统计分析,得到如下统计结论:深圳地区花岗岩孤石主要成份是微风化花岗岩,60%以上分布在强风化花岗岩层中,残积层和全风化层中也有分布,孤石层面分布高程集中在40.00~70.00m(黄海高程)区间内;80%的孤石揭示“厚度”不超过2.50m,三分之二花岗岩孤石主要发育一层,随着发育层数的增多,出现频率锐减.  相似文献   

11.
International unity is becoming ever stronger in this country owing to an increasing similarity in the development of the cultural environment. This comprises the provision of all the country's republics with a sufficient number of schools, theatres, and other institutions and cultural information media in accordance with the needs of the population. An important part is played by the rise in ‘the general educational level, as well as the level of professional qualifications and skills. Among all the Soviet nations and nationalities, this rise being more rapid among formerly backward peoples. Prominent among the factors of internationalization is the progressive development of the nationalities’ cultural resources, while professional culture is being increasingly brought within the reach of the masses.The implementation of the nationalities policy promotes the all-round development of all Soviet nations and nationalities, their drawing together, the upsurge of the individual capabilities of every Soviet citizen.  相似文献   

12.
It is known from observations that the center of mass of the Moon does not coincide with the geometric center of its figure, and the line connecting these two centers is not aligned with the direction toward the center of the Earth, instead deviating toward the Southeast. This stationary deviation of the axis of the inertia ellipsoid of the Moon to the South of the direction toward the Earth is analyzed. A system of five linear differential equations describing the physical libration of the Moon in latitude is considered, and these equations are derived using a new vector method taking into account perturbations from the Earth and partly from the Sun. The characteristic equation of this system is obtained, and all five oscillation frequencies are found. Special attention is paid to the fifth (zero) frequency, for which the solution of the latitude libration equations are stationary and represents a previously unknown additional motion of the rotational axis of theMoon in a cone with a small opening angle. In contrast to the astronomical precession of the Earth, the rotation of the angular-velocity vector is in the positive direction (counter-clockwise), with the period T 3 = 27.32 days. On this basis, this phenomenon has been named “quasi-precession.” This quasi-precession leads to a stationary inclination of the major axis of the inertia ellipsoid of theMoon to the South (for an observer on Earth), making it possible to explain one component of the observed deviation of the center of mass of the Moon from the direction toward the Earth. The opening angle of the quasiprecession cone is approximately 0.834″.  相似文献   

13.
14.
Chronological analyses of correlations between certain global repeating events (mass extinctions of marine organisms, meteorite impacts, and flashes in the frequency of geomagnetic reversals) during the Phanerozoic Eon and the motion of the solar system in the Galaxy are presented for five rotationally symmetrical models for the regular Galactic gravitational field. Thirteen of sixteen mass-extinction events can be described by a repetition interval of 183±3 million years. This is in agreement with the anomalistic period (interval between two subsequent passages of the Sun through the apocenter of its Galactic orbit) in the model of Allen and Martos. The positions of the minima and maxima in Gaussian functions approximating the frequency distribution for geomagnetic reversals also agree with the times of passage of the Sun through the apocenter and pericenter, respectively, of its Galactic orbit in this model. The maximum in the distribution of the deviations of the dates of mass extinctions from the nearest dates of impacts of large, crater-forming bodies is close to zero, providing evidence that many such events are correlated. As a rule, extinctions follow impact events. The impacts of large bodies have occurred most often when the solar system passes through the Galactic plane, while mass extinctions occur more often at some distance from the Galactic plane (about 40 pc). As a rule, intervals of increases in the frequency of geomagnetic reversals coincide with dates of impacts of large bodies. At the same time, these intervals do not show a clear correlation with the dates of mass extinctions. The intensity of mass extinctions, like the energy released by impacts, is consistently higher in periods when the Sun is moving from the apocenter toward the pericenter of its orbit, than when it is moving from the pericenter toward the apocenter. Thus, there is evidence for a variety of relationships between repeating global events in the Phanerozoic and the motion of the Sun in the Galaxy. Long-period variations in the frequency of geomagnetic reversals are correlated with the orbital motion of the Sun, and increases in the frequency of geomagnetic reversals are correlated with impacts. Mass extinctions are correlated with the impacts of large bodies, whose motions may have been perturbed by clouds of interstellar material concentrated toward the Galactic plane and by the shock front associated with the Perseus spiral arm, through which the solar system passes. The velocity of the Sun relative to the spiral pattern is estimated.  相似文献   

15.
从榴辉岩与围岩的关系论苏鲁榴辉岩的形成与折返   总被引:4,自引:1,他引:4       下载免费PDF全文
位于华北和扬子两板块碰撞带中的苏鲁榴辉岩形成的温压条件不但是超高压,而且是高温。榴辉岩的PTt轨迹表明其为陆-陆磁撞俯冲带的产物。榴辉岩的区域性围岩花岗质片麻岩为新元古代同碰撞期花岗岩,榴辉岩及其他直接围岩皆呈包体存在于其中,并见新元古代花岗岩呈脉状侵入榴辉岩包体中。区域性围岩新元古代花岗岩的锆石中发现有柯石英、绿辉石等包裹体,表明新元古代花岗岩的组成物质也经受过超高压变质作用,且榴辉岩与围岩新元古代花岗岩的锆石U-Pb体系同位素年龄基本相同。但新元古代花岗岩所记录的变质作用和变形作用期次(或阶段)却少于榴辉岩。椐上述可得如下推断:超高压榴辉岩与新元古代花岗岩岩浆是同时在碰撞带底部(俯冲板块前部)形成的;榴辉岩的第一折返阶段是由新元古代花岗岩岩浆携带上升的,其第二折返阶段是和新元古代花岗岩一起由逆冲及区域性隆起而上升,遭受剥蚀。  相似文献   

16.
某高速公路下伏煤矿采空区稳定性分析   总被引:10,自引:0,他引:10  
在论述某高速公路下伏砦脖煤矿采空区地质、采矿和工程地质特征的基础上, 进行了稳定性数值模拟分析, 定性与定量地分析与评价了该煤矿采空区的地表变形特征及稳定性。研究结果表明: 该煤矿采空区的变形尚未完成, 对拟建的高速公路将产生很大的危害, 必须采取相应的工程治理措施。   相似文献   

17.
18.
摩擦桩基桩土间极限摩阻力取值问题探讨   总被引:1,自引:0,他引:1  
陈银生 《世界地质》1999,18(1):54-59
通过对广珠东线高速公路横沥大桥的试桩及土体的工程地质条件分析,总结出影响摩擦桩基桩土间极限摩阻力取值的一般问题以及解决问题的方法和措施。  相似文献   

19.
In order to characterise the influence of the heavyrains on the observed landslides during the 1996–1997hydrological cycle, rainfall records for the last 100years are analysed from 104 stations in easternAndalusia. Regarding the amounts of rain recordedbetween October 1996 and March 1997 in the 104stations studied, 31 presented new all-time records;15 presented values that were 80–100% of thepre-1995 record; 49 stations, 80–50%; and 9stations, < 50%. A map has been devised of thesusceptibility of the materials through which thesouth-eastern Andalusian road network crosses,together with an inventory of the damage caused byinstability phenomena on banks and cuttings of theroad network during the winter of 1996–1997. Therelationships between the rainfall during the studyperiod, the damage caused to the road network and thesusceptibility of the materials affected are analysed.The results indicate that there is a clearcorrespondence between the rainfall recorded and thesusceptibility of the materials with the inventorieddamage. It is concluded that the widespread seriousdamage caused in early 1997 to the roads andsurrounding areas in the Alpujarra region and thecoast of the Province of Granada was mainly caused bythe extraordinarily heavy rains. However, considerablyless damage was observed where the susceptibility ofthe terrain is low, thus highlighting the extremeusefulness of terrain-susceptibility maps for riskprevention and territorial planning.  相似文献   

20.
The structure of the eastern Pyrenees consists mainly of south-directed thrusts involving basement and cover rocks. An antiformal stack developed by the piling up of basement thrust sheets which outcrop in the Axial zone. These structures account for a thin-skinned thrust model rather than a vertical fault model in which the Axial zone would be essentially autochthonous, and the North-Pyrenean fault the axial plane of a fan thrust system. New data from the Eastern Pyrenees and the thin-skinned model suggest that(1) the structure east of the Pedraforca nappe is similar to that of the Central Pyrenees; (2) the cover rocks of the South-Pyrenean units and of the Axial zone-after restoration—built up a northwards-thickening prism consistent with the existence of a unique Pyrenean sedimentary basin during Mesozoic time; (3) the Axial zone is only a complex antiformal stack developed as a part of South-Pyrenean system related to the Paleogene thrusting-tectonics. The Axial zone palaeogeographic area had no special meaning during Mesozoic time.  相似文献   

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