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抗滑桩是滑坡整治工程设计中的主要技术措施之一，本文通过对抗滑桩的力学性质和受力状态进行客观分析和评价，提出两种新型抗滑桩结构及其实践应用的可行性，即变截面抗滑桩和推力传递抗滑桩，特别是，推力传递抗滑桩技术，可以节省钢材８０％以上，从而大大地降低了抗滑工程造价，并且，从根本上改变了传统的抗滑桩的力学性质和桩身受力状态，值得深入研究、推广和应用。 相似文献
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通过对宝鸡黄土塬区的马兰黄土岩土物理力学性质特征及湿陷特性的研究探讨，提出了马兰黄土的最佳基础方案和利用治理方法。 相似文献
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西秦岭铀矿床成矿环境与围岩物理力学性质关系 总被引：2，自引：2，他引：2
成矿环境的含义并不局限于构造断裂带本身，还涉及到围岩的物理力学性质问题，一般而言，围岩的物理力学性质对成矿环境的塑具有决定性影响。这就是为什么在一个地区同时形成的断裂构造中并非都能产矿，甚至在同一条含矿构造断裂带上也并非各地段都有矿产出的原因。为了探索成矿环境的形成与围岩物理力学性质的关系，本文研究了该区围岩的物理力学性质，探讨了成矿环境对围岩物理力学性质的选择。 相似文献
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岘山垭公路路堑滑坡膨胀土特性及机制探讨 总被引：4，自引：1，他引：4
襄樊岘山垭地区膨胀土滑坡是影响公路交通的重大地质病害。曾投入了大量资金进行整治均没有收到良好效果。在探明岘山垭膨胀土滑坡的一些重要性质基础上，利用X射线衍射仪（XRD）、X射线荧光光谱（XRF）分析仪和扫描电子显微镜（SEM），综合常规物理力学实验，对滑坡膨胀土物理性质、微观结构进行了深入研究。以此为基础，探讨了该区膨胀土一些特性在滑坡形成演化中的作用，进一步阐明了该滑坡的形成机制，总结了膨胀土滑坡的一些重要规律，对于深入研究膨胀土滑坡及滑坡整治有十分重要的意义。 相似文献
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郜城井田滑动构造带与矿井地质灾害 总被引：3，自引：0，他引：3
王志荣 《地质灾害与环境保护》2003,14(4):21-24
对郜城井田F1滑动带的岩性、结构、力学性质和水动力学特征进行了研究，对矿山开拓过程中的突水和矿井碎屑流的成因作了探讨。并在大量矿井调查和野外勘探资料的基础上，提出了对矿井地质灾害的预测和防治方案。 相似文献
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云南大保高速公路K399滑坡活动特征及治理设计 总被引：4，自引：0，他引：4
朱平生 《地质灾害与环境保护》2002,13(4):28-32
云南大保高速公路K399滑坡，于1999年4月16日初次滑动，以后又经过多次滑动和整治，但滑坡仍不稳定。在总结和回顾该滑坡发展变化的基础上，根据大量的地质资料，分析了滑坡的地质条件、成因和力学机制。确定其力学性质为牵引-推移式大型碎石土-岩质滑坡。对涔坡稳定性作了定性、定量分析和评价。根据该滑坡活动特点和滑坡特征，经综合分析研究和计算后，采取以桩板墙、预应力锚索抗滑桩为主体工程，辅以锚固、护坡和排水的综合治理措施，既根治了滑坡，又获得了良好的治理效果，为大保高速公路的全线贯通争取了时间。 相似文献
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详细介绍了江门市某病挡土墙的工程治理实践，通过对病害挡土墙的原因分析，提出了合理的整治方案及施工处理措施，达到预期整治效果。 相似文献
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比萨斜塔从修建至今800余年缘何斜而不倒,这是一个颇具吸引力的问题。围绕这一问题,从土材料的变形机制入手,介绍了其变形的加载次序相关性。经微分学中曲线积分路径无关的充分必要条件检验,证实了经典岩土本构模型Cam-clay对土材料应变的加载应力路径相关性描述与试验相符。土材料变形与加载次序的相关性在应用增量本构模型计算中,实际就体现在模型描述于数学上的曲线积分路径相关性上。完全一样的比萨斜塔,完全一样的地基,仅修建时间长短的不同便造就了地基土中有效应力加载路径的显著差异,从而极大地影响了与加载应力路径相关的广义剪应变的发展情况,最终决定了地基土的破坏与否,建筑物的倒塌与否。从这个角度,深刻巧妙地揭示出比萨斜塔数百年来斜而不倒的数学奥秘。在解释Burland等对比萨斜塔一次修建完工将会倒塌的观点同时提出猜想：如果进行更加缓慢的修建,地基土有效应力路径会更加远离临界状态应力线,那么比萨斜塔今天的倾斜程度可能大为降低。 相似文献
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观光塔边坡的稳定性分析与治理措施 总被引：1，自引：0，他引：1
分析了观光塔边坡的失稳破坏机制,并应用不确定性方法对该边坡进行了稳定性分析,结果表明,坡脚陡倾岩层是阻止该边坡继续滑移的有利因素,地下水是控制该边坡稳定的主导因素.最后,基于机制分析提出了针对性的治理措施. 相似文献
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西安地铁二号线下穿城墙及钟楼保护措施研究 总被引：4，自引：0，他引：4
针对西安地铁二号线穿越国家级文物--城墙北门、南门及钟楼保护区在施工期以及运营期对古建筑物的影响,提出1套城墙北门、南门及钟楼的具体有效的保护措施。对比分析了穿过城墙北门、南门及钟楼的地铁几种设计施工方案,最终采纳地铁线路双侧分绕古建筑物、隔离桩基础加固以及加固古建筑物上部结构的施工方案。利用有限元软件对处理效果分析得出,城墙北门、南门及钟楼加固后地铁影响效果减小2/3。施工期监测数据表明,古建筑物沉降位移比实际预测位移要小,沉降位移均在保护设计范围之内,论证了保护措施有效性和合理性。同时,分析了地铁运营振动对城墙影响,并提出减振措施以及减振效果分析。通过方案选取、数值分析、具体实施以及实时监测,提出并论证一套具有很强实用价值的隧道穿越古建筑物保护措施。 相似文献
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坐落于上海的金茂大厦、上海环球金融中心和上海中心大厦三幢闻名世界的超高层建筑的基础均为补偿深埋桩筏基础。在补偿深埋桩筏基础设计中如何充分考虑补偿基础的优越性,如何考虑深埋基础的抗风能力,是值得研究的问题。利用高层建筑与地基基础共同作用的分析方法,结合统计-经验公式对该三幢大楼的桩筏深基础进行了再分析。通过再分析在节约相当数量的桩之后,其地基承载力和变形仍然能够满足设计要求。同时在再分析中进一步探讨优化设计的能力,论证地下连续墙可以分担相当数量的荷载。相关案例的再分析对进一步完善补偿深埋桩筏基础设计理论提出建议,可为国家节省大量投资。 相似文献
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Alessandro Amorosi Irene Sammartino Giovanni Sarti 《Environmental Earth Sciences》2013,69(5):1661-1671
Identification of reliable background values of potentially toxic metals in sediments requires detailed integration of geochemical data with accurate sedimentological studies. Through analysis of 60 soil samples from the Pisa coastal plain, this study shows to what extent sediment provenance and facies characteristics may influence the natural distribution of potentially toxic metals (Cr, Ni, Cu, Zn, Pb) within alluvial and coastal sediments. Metals supplied to the alluvial plain are mostly concentrated within the finest sediment fraction (floodplain clays), while coarser crevasse and overbank deposits exhibit invariably lower metal contents. Beach-ridge sands display the lowest metal concentrations. Transport of ophiolitic detritus by the longshore drift may account for locally high Cr concentrations within beach deposits. Geochemical fingerprinting of individual facies associations in terms of natural metal contents results in the construction of a geologically-based geochemical map. This map offers a more reliable depiction of spatial distribution of background levels than interpolation techniques based uniquely upon statistical methods. Matching background values against metal concentrations from topsoil samples leads to the reliable assessment of the pollution status of Pisa coastal plain. Metal contents exceeding the threshold values designated for contaminated areas (Cr) simply reflect catchment geology, and are not the product of artificial contamination. On the other hand, anthropogenic disturbance may be detected even where metal contents (Pb, Cu) lie below the threshold values. The use of sedimentological criteria is presented here as a pragmatic tool to enhance predictability of natural metal contents in sediments, with obvious positive feedbacks for legislative purposes and environmental protection. 相似文献
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Summary About 90 samples of mortars from historical buildings in Pisa have been analysed and compared with some samples of ancient mortars characterized by pozzolanic aggregates. Chemical (XRF), mineralogical (XRD) and petrographical (optical microscopy) data have been collected on bulk samples. An X-ray energy-dispersive system (EDS) attached to a SEM was used to determine the chemical compositions of binder, clots and pozzolanic grains (whenever present). The binder components which could not be directly assessed (CO2, H2O+) have been indirectly derived through a computation method.Data collected suggest that the main stock of analysed samples (i.e., mortars from Pisa monuments) contains two principal types of binder: the first type corresponds to a common carbonated lime; the second type is a hydraulic lime, where the carbonate component is associated with an important silicate fraction, which constitutes 13 to 89 wt% of the total binder (on average 47%). This hydraulic type had a widespread application in the construction of ancient monuments in Pisa; for example, it was constantly employed in the building of the famous Leaning Tower. This study shows that the silicate fraction of such hydraulic mortar, which is amorphous to X-ray diffraction, is made up by a hydrated calcium alumino-silicate having a very low Al2O3/SiO2 ratio (on average 0.125). On the basis of chemical and optical characteristics of hydraulic mortar binders from Pisa and the results of laboratory tests, as well as through comparison with the characteristics of ancient hydraulic mortars having pozzolanic aggregates, it is concluded that such mortars were prepared most likely by mixing slaked lime with a reactive, highly siliceous material such as a diatomaceous earth.
Über Bindemittel in antiken Mörteln
Zusammenfassung Etwa 90 Mörtelproben von historischen Gebäuden in Pisa wurden analysiert und mit Proben von antiken Mörteln, die durch pozzolanische Aggregate charakterisert sind, verglichen. Chemische (XRF), mineralogische (XRD) und petrographische (optische Mikroskopie) Daten wurden an den Gesamtproben ermittelt. Ein an ein SEM angeschlossenes energiedispersives System (EDS) wurde für die Bestimmung der chemischen Zusammensetzung des Bindemittels, der Mörtelklümpchen und der pozzolanischen Körner (sofern vorhanden) verwendet. Die Komponenten des Bindemittels, die nicht direkt gemessen werden konnten (CO2, H2O+) wurden indirekt durch ein Berechnungsverfahren ermittelt.Die gesammelten Daten belegen, dass die meisten untersuchten Proben (i.e. Mörtel von Monumenten aus Pisa) zwei Typen von Bindemittel enthalten: Der erste Typ entspricht einem gewöhnlichen karbonatisierten Kalk. Der zweite Typ ist ein hydraulischer Kalk, in dem die Karbonatkomponente mit einer mengenmäßig bedeutenden Silikatfraktion assoziiert ist, die 13–89 Gew.% des gesamten Bindemittels ausmachen kann (durchschnittlich 47%). Dieser zweite Typ wurde häufig beim Bau alter Monumente in Pisa verwendet, z.B. wurde er ständig beim Bau des Schiefen Turms herangezogen. Diese Studie zeigt, dass die Silikatfraktion dieses hydraulischen Mörtels, die röntgenamorph ist, aus einem hydratisierten Aluminosilikat mit einem niedrigen Al2O3/SiO2 Verhältnis (im Durchschnitt 0.125) besteht.Auf Basis der chemischen und optischen Charakteristika des hydraulischen Mörtel, die pozzolanische Aggregate führen, schließen wir, dass diese Mörtel höchstwahrschein lich durch Mischung von Löschkalk mit sehr reaktivem, silikatischen Material, wie etwa Diatomeenerde hergestellt wurden.相似文献
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W. K. Witt 《Australian Journal of Earth Sciences》2013,60(1):81-99
The Tower Hill gold deposit is distinguished from most Archaean lode deposits of the Yilgarn Craton by virtue of its formation early in the regional deformation history and its consequent deformation. The deposit is located in ultramafic schist, adjacent to the contact with a small pluton of biotite monzogranite that intrudes pervasively foliated granodiorite, the dominant component of the Raeside Batholith. Gold, accompanied by local concentrations of bismuth minerals and molybdenite, occurs in a number of quartz vein ‘packages‘. Mineralised quartz veins at Tower Hill lie within an envelope of potassic alteration (talc‐biotite‐chlorite‐pyrite schist), up to several hundred metres wide. They are spatially and temporally associated with the biotite monzogranite and felsic porphyry intrusions, and their deformed equivalents. The deposit lies in a broad zone of ductile deformation (the Sons of Gwalia Shear Zone). Within the altered ultramafic schist, thin units of felsic schist, derived from biotite monzogranite and felsic porphyry, provided sites of contrasting competency that localised quartz vein formation. The mineralised quartz veins were subsequently deformed during alternating periods of shortening and extension, probably related to the syntectonic, solid‐state emplacement of the Raeside Batholith. These deformations pre‐dated strike‐slip movement on the Cemetery Fault, which truncates the ductile fabrics of the Sons of Gwalia Shear Zone, south of Tower Hill. In terms of the regional deformation history, gold mineralisation at Tower Hill formed during early D2 (regional upright folding); subsequent deformation of the orebody pre‐dated D3 (strike‐slip movement on the Cemetery Fault). The nearby Sons of Gwalia and Harbour Lights deposits also probably formed at an early stage, in contrast to most lode gold deposits in the Yilgarn Craton, which formed during or after D3. 相似文献
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Predicting environmental conditions to minimise salt damage at the Tower of London: a comparison of two approaches 总被引：1，自引：0，他引：1
Clifford A. Price 《Environmental Geology》2007,52(2):369-374
The paper compares the results of two studies of salt damage at the Wakefield Tower, Tower of London. The first, in 1993,
was based on semi-quantitative salt analysis and hygroscopicity measurements. The second was based on quantitative analysis
and a thermodynamic model, ECOS. Both studies aimed to predict environmental conditions that would minimise salt damage to
the interior stonework. Their predictions are markedly different, and this paper examines the reasons for the differences.
It is shown that hygroscopicity alone is not a reliable indicator of crystallisation from mixed salt solutions.
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