共查询到18条相似文献，搜索用时 109 毫秒
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结合烟台港三突堤集装箱码头工程现浇混凝土胸墙施工，分析论述了无害裂缝与有害裂缝的区分，以及裂缝缺陷的成因和影响，提出了控制要点和防治措施，在施工中应用后取得了预期效果。 相似文献
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浅议混凝土的温度裂缝 总被引：1，自引：0，他引：1
混凝土温度裂缝是一种比较难控制的缺陷的裂缝的产生原因是水泥的水化热,实践证明,采用高质量的水泥和恰当的水泥用量配比,加设钢筋网,加上良好的养护和妥善处理,能使大体积混凝土温度裂缝降低到最低限度,可以保证施工质量。 相似文献
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非稳定性混凝土裂缝的成因与处理 总被引：1，自引：0，他引：1
裂缝渗漏是引起混凝土破坏的原因之一,而非稳定性裂缝更以其不稳定的特性难于处理。本文从其危害性入手,分析了裂缝成因,介绍了一种针对非稳定性裂缝的堵漏施工方法。 相似文献
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Norman Wells油田位于加拿大西北地区，距离北极圈60km，其产油层为泥盆系的碳酸盐岩岩岸复合体。该岩岸复合体在岩岸内的最大厚度可达130m，向盆地方向由于岩岸边界的退覆和沉积层的尖灭其厚度逐渐减薄。Norman Wells油田是一个以油为主的油田，其原始石油地质储量约为108百万方（680百万桶）。储层的基质渗透率很低（平均为2-4毫达西），但裂缝很发育。以前对Norman Wells油田所做的三维地质建模并没有尝试结合裂缝的渗透率，结果是在静态和动态储层模型与油田开发的历史数据之间产生了误差。最近，针对全油田范围的渗透率建立了一个量化基质和裂缝性能的共同影响的三维模型。基质和裂缝性能被分开进行了模拟，然后合成了一个完整的渗透率模型。基质的性能受沉积相和层序地层格架的控制。使用岩芯和测井数据，结合沉积相和地层信息可以建立三维的孔隙度和渗透率模型。裂缝渗透率则是分两步来建立的，第一步，注水数据和生产数据被用来分离并模拟储层中裂缝所产生的渗透率（裂缝所提高的渗透率）；第二，从岩芯、成像测井和露头等数据中测得的裂缝的几何属性（方向、规模、密度）被用来量化裂缝的几何参数以及由裂缝所导致的渗透率的各向异性（定向渗透率）。构造、地层和沉积相等信息也被用在了三维模型格架中，这些信息可以指导对井控范围以外的裂缝渗透率所进行的预测。模拟结果显示，裂缝不同程度地提高了基质的渗透率，而且，如果没有裂缝的增渗作用，Norman Wells油田的绝大部分油层都将是非经济的油层。在油田的大部分地区中，裂缝网络均有效地提高了基质的渗透率，而且并没有明显地影响地层的一致性。不过，也有一些地区的储层中裂缝十分发育，并导致了注入水的突破，降低了储层的一致性。裂缝性能的变化具有一定的规律，主要与构造位置和碳酸盐岩岩岸的地层力学特征有关。在岩岸的边缘和较陡的上倾（东北方向）构造斜坡上的储层中，裂缝的作用是最强的。应用这一新的模型，未需对流体模型的渗透率做多少修改，我们就迅速地获得了对生产动态史的拟合。将动态数据用于三维地质模型有两个的优点：1）可以降低对调整流体模型渗透率的需求，并产生一致性更强的动静态模型；2）用地质信息来指导剩余渗透率的分布，避免了对渗透率参数的针对性调整。这种新的动静态模型正被用于储层和产能预测、时机判断和油田管理等方面。 相似文献
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通过对温度与收缩应力的分析和计算,判定了宁波市姚江船闸闸室薄壁墙身出现的裂缝属温度与收缩引起的裂缝,并有针对性地提出了适当缩短结构分段长度、加密防裂钢筋和改进施工工艺等措施,这些措施在姚江船闸闸室后续工程的施工中被证明是行之有效的,从而杜绝了由温度与收缩应力引起的裂缝再次出现。 相似文献
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在建筑工程中,现浇钢筋混凝土楼板出现裂缝的情况较多,这已成为影响住宅工程质量的一大通病。对其产生裂缝的原因进行了分析,并结合工程实际,就预防和综合治理提出了较全面的对策。 相似文献
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3DMove裂缝预测技术在埕北30潜山裂缝预测中的应用 总被引：1，自引：0，他引：1
裂缝的准确描述和预测是裂缝性储层有效开发的关键,由于裂缝性储层具有极强的非均质性和致密低渗透性,储层发育的控制因素很多,因此裂缝储层空间分布预测的难度非常大,给裂缝油藏的进一步勘探开发带来很大困难。本文应用3DMove构造正反演裂缝预测技术预测古生界潜山顶和太古界顶两套地层的裂缝分布和方位,并从应力场的角度对裂缝的开启性作出分析。将该技术应用于胜利油田埕北30潜山,通过与已钻井资料对比分析,预测结果与实际井的裂缝发育情况有较好的一致性。 相似文献
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BZ19-6气田变质岩潜山储层结构复杂、多样，裂缝发育且非均质性强。在储层评价中，识别有效的裂缝是一个紧迫的难题，而这对于该气田的勘探开发具有重要的意义。以岩性主要为花岗片麻岩、夹少量侵入岩的太古界为研究层位，通过对常规测井曲线进行重极标差（R/S）分析，以识别研究层位的裂缝发育程度，并通过计算Lg(R/S)的牛顿二阶差分值预测裂缝的发育位置。进一步将R/S分析结果与岩芯薄片裂缝观察统计和电成像图解释结果进行对比，建立了利用赫尔特指数识别花岗片麻岩储层裂缝发育程度分类标准。研究表明：(1)将R/S分析和牛顿差分法相结合改进的裂缝识别方法，在变质岩储层裂缝评价中具有可行性，可识别宽度>0.005 mm的裂缝；(2) Lg(R/S)曲线二阶差分值能够准确地识别天然裂缝的发育位置，并且KRxo与裂缝线密度呈正相关，相关性高；(3)岩性各向异性和裂缝充填情况对常规测井曲线R/S分析方法识别裂缝精度有影响。 相似文献
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Temperature and Stress Analysis of An Experimental Model of Prestressed Lightweight Concrete Platform 总被引：5，自引：2，他引：3
—This paper presents an experimental study of a prestressed lightweight concrete platform mod-el with a tank and five steel columns.This platform can be used not only for extraction but also for storageof oil and is suitable for the Bohai Sea and other shallow seas of China.The platform is subjected to tem-perature.load.or both.The corresponding temperature distribution.strains.cracks.and vulnerable partsof the platform are analyzed respectively.By use of the finite element method and empirical formulas.thetemperature field of the model is analyzed.The results agree with the experimental results.thereby veri-fying the reliability of these two calculating methods.The paper provides an experimental basis for the de-sign of the bearing capacity and normal service state of prestressed concrete platforms. 相似文献
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The main objective of the present study is to examine the residual ultimate strength characteristics of steel plates with cracking damages under axial compressive actions through experimental investigations. The present study is a sequel of the author's previous paper (Paik, J.K., Satish Kumar, Y.V., Lee, J.M., 2005. Ultimate strength of cracked plate elements under axial compression or tension. Thin-Walled Structures, 43, 237–272). In contrast to the previous paper which dealt with transverse cracks located in the direction normal to the axial loading direction, the present paper is concerned with longitudinal cracks which are located in parallel to the axial loading direction. Similar to the previous paper, the orientation/location and size of cracks inside the plates are varied for the present experimental investigations. The details of experimental results are documented. The database and insights developed from the present work will be useful for cracking damage-tolerant design of steel-plated structures and also for condition assessment or health monitoring of aging steel-plated structures. 相似文献
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A three-dimensional thermo-mechanical coupled finite element model is built up to simulate the phenomena of dynamical contact and frictional heating of crack faces when the plate containing the crack is excited by high-intensity ultrasonic pulses. In the finite element model, the high-power ultrasonic transducer is modeled by using a piezoelectric thermal-analogy method, and the dynamical interaction between both crack faces is modeled using a contact-impact theory. In the simulations, the frictional heating taking place at the crack faces is quantitatively calculated by using finite element thermal-structural coupling analysis, especially, the influences of acoustic chaos to plate vibration and crack heating are calculated and analysed in detail. Meanwhile, the related ultrasonic infrared images are also obtained experimentally, and the theoretical simulation results are in agreement with that of the experiments. The results show that, by using the theoretical method, a good simulation of dynamic interaction and friction heating process of the crack faces under non-chaotic or chaotic sound excitation can be obtained. 相似文献
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Deep-seated gas in seabed sediments migrates upwards from effect of external factors, which easily accumulates to form gasbags at interface of shallow coarse-fine sediments. Real-time monitoring of this process is important to predict disaster. However, there is still a lack of effective monitoring methods, so we attempt to apply multi-points pore water pressure monitoring technology when simulating forming and dissipation of gasbags in sediments through laboratory experiment. This study focuses... 相似文献
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于2012年春季(5月)调查了渤海湾天津近岸海域的网采浮游植物群落,经初步分析发现网采浮游植物共2门17属28种,其中硅藻26种,占种类组成的92.9%;甲藻2种,占种类组成的7.1%。调查海域浮游植物以广温型近岸种为主,主要优势种为柔弱几内亚藻Guinardia delicatula、中华齿状藻Odontella sinensis、布氏双尾藻Ditylum brightwellii和格氏圆筛藻Coscinodiscus granii;调查海域网采浮游植物细胞丰度的分布主要由浮游硅藻的分布所决定,高值区主要分布在塘沽、大港和歧口周围海域;20个站位根据浮游植物的物种及丰度相似性可以划分为5组;浮游植物物种多样性指数在0.43～3.59之间,平均为2.15,多样性指数出现由南、北向中央逐渐缩小的趋势;水温、DO、pH值和无机氮与浮游植物种类组成和细胞丰度分布呈最大等级相关,这4个环境因子是对观察到的群落结构的最好解释。 相似文献
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G. I. Gorchakov E. G. Semutnikova E. V. Zotkin A. V. Karpov E. A. Lezina A. V. Ul’yanenko 《Izvestiya Atmospheric and Oceanic Physics》2006,42(2):156-170
Variations in the concentrations of gaseous pollutants in the air basin of Moscow are statistically analyzed. The basic statistical characteristics of variations in the concentrations of carbon monoxide, nitric oxide, nitrogen dioxide, ozone, formaldehyde, and a number of aromatic compounds are calculated. The main properties of intradiurnal, synoptic, seasonal, and interannual variations in the concentrations of gaseous pollutants are described. The power spectral densities of variations in the concentrations of carbon monoxide and nitrogen oxides are analyzed. The contributions made by variations in the concentration of carbon monoxide on different time scales to the total variance are calculated. The effect of the atmospheric air polluted with carbon monoxide and nitrogen oxides on the ecological situation in the city is estimated. The probabilities of an excess over the single maximum allowable concentrations are determined for carbon monoxide and nitrogen oxides. The absorption of shortwave solar radiation by nitrogen dioxide in the atmospheric boundary layer is estimated. 相似文献