裂缝的

On the basis of equivalent penetrate theory , the relation of fracture permeability and asperity .spacing is derived.

根据平行板模型研究了裂缝的流动特征，由等效渗流阻力可以得到裂缝渗透率和裂缝开度、间距的关系。

To give the definition of the mass concrete and to concrete\'s cracks together with practical meanings of control ,and give a brief review on the research in the field at home and abroad, at last, methods to control temperature crack of the mass concrete from several aspects such as design measures,concrets material, construction schedules.etc are summed up; To explain the physical mechanics of the concrete and computing methods-Difference Method and Finite Element Method, and illustrate the application of their specific methods repectively;Several temperature factors that can influence the temperature stress of mass concrete baseplate are analyzed. The influence degree of temperature factor can be got through the ANSYS simulation computation the control of temperature can control the temperature stress, consequently control the temperature crack of mass concert baseplate; through the influence of the crack resistance ability of mass concrete baseplate which takes the reinforcement as a part is analyzed. By ANSYS simulation, the best suited volume ratio of reinforcement is found out, at same time the layout of reinforcement with the same volume ratio can also affect the resistance ability of mass concrete baseplate. Sum up of above analysis, anti-crack function of steel bar in early mass concrete baseplate is obvious, so it\'s necessary to consider beneficial effect of construction steel bar in research of temperature control on mass concrete baseplate.

本文先容了大体积混凝土及混凝土裂缝的基本概念，对国内外在这个领域里的研究现状作了扼要叙述，并从结构设计、混凝土材质、施工措施等方面总结了大体积混凝土温度裂缝控制的方法及防止措施；阐述了混凝土的基本物理力学性能，总结了大体积混凝土温度计算的方法——差分法和有限元法，并分别举例说明其具体应用的方法；分析了影响大体积混凝土底板温度应力的几种温度因素，利用ANSYS模拟计算，得出了每种因素的影响程度，通过分析提出了在这几种温度影响因素下如何通过控制温度以达到控制温度应力从而来控制裂缝的具体建议；针对大体积混凝土基础底板中配筋的不同对混凝土底板抗裂能力的影响不同，利用ANSYS进行模拟分析，得出底板中最合适的体积配筋率，同时分析了在相同体积配筋率下钢筋的具体布置对大体积混凝土基础底板抗裂能力的影响，分析表明，配置钢筋对混凝土结构的开裂阻止作用明显，在研究大体积混凝土温度裂缝题目时，要考虑钢筋在其中的有利作用。

In this paper, the factors that may cause crack breaking of concrete pavement of several built highways were analyzed systematically and thoroughly. From analysis to site experiments and calculation, it is believed that crack breaking is mainly caused by factors as follows: 1 、 Unqualified sedimentation and losing stabilization of the roadbedinduced crack in the early; 2、 Construction technology、 materials and incorrect treatment methodswere adopted;3 、 Crack breaking induced by thermal stress; 4、 Water cant circulate makes crack cause;With regard to the afore-mentioned problems, corresponding preventive measures, qualified control indices and site control approach are presented based on analysis theory and site experiments.

本文在全面系统地分析已建成的高速公路水泥混凝土路面产生的原因的基础上，通过现场试验及计算分析，确定了高速公路水泥混凝土路面裂缝的主要影响因素有以下几个方面： 1、路基的不均匀沉降、失稳是早期裂缝产生的主要因素； 2、施工工艺、材料问题及养护方法不当； 3、温度应力产生的裂缝； 4、排水不畅影响裂缝产生；针对上述问题，通过理论分析及现场数据提出相应的质量控制目标、现场控制方法。

The mechanism of lock corridor crack is rather complicated due to the unique structure of corridor. As a result construction technique improvement cannot totally eliminate corridor crack occurrence. According to the construction process and results of Jinghang Cannel Huaiyin 3rd Lock,certain technical measures and improvements in construction techniques,can efficiently control the corridor crack and avoid the occurrence of crack as much as possible.

船闸廊道裂缝的产生机理较为复杂，由于廊道独特的结构形式，仅仅从改善施工工艺方面来完全消除廊道裂缝的出现是很难的，从本次京杭运河淮阴三线船闸工程实施过程及结果来看，通过一定的技术措施和改善施工工艺，可使廊道裂缝得到有效的控制，同时避免了有害裂缝的产生。

The elastic stress diagram design method is behind the times and cant meet the command in practice.In the paper the author collected and analyzed a large amount of data about the SLRCP on several typical domestic model experiments and the projects in practice. By summarizing and analyzing the data, the author set up a typical computing model and analyzed the model by the software ANSYS, by reading the output data of the stress and the crack from the program, combined with the experimental results, the author summarized the destroy procession of the stock. The paper also discussed the influence of other main factors to the crack and the stress besides the internal water pressure, such as the concrete material, the dimension of stock and the way of laid-out steel bars.

本文通过对大量实际工程中的坝后背管资料的收集、归纳和分析，选取了具有代表性的计算模型；用有限元软件ANSYS计算了典型坝后背管结构在实际内水压力作用下的应力分布和裂缝发展情况；以国内几个有代表性的模型试验和有限元计算的成果为依据，分析了在内水压力作用下钢衬钢筋混凝土压力管道管壁裂缝的特点，并尝试总结出此种管道的裂缝出现的原因及其发展规律，同时确定了坝后背管结构极限状态的新的定义方式——以坝后背管的裂缝宽度来定义。

The results show that the existing of fractures has influence on percolation flow characteristics of low permeability reservoir.

实验结果表明，裂缝的存在对低渗透储层的渗流特征有明显的改造，裂缝开启前，储层渗流可以看作是基质岩石渗流，裂缝对渗流的影响不大；裂缝开启后，由于其渗流能力较强，将发挥主要的渗流通道作用。

In order to control the surface crack damage of huge thick collapsible loess caused by mining effectively,the distribution rule of stress-strain in top interface of the base rock and the relation of which and the surface crack were obtained using the probability integral method.

为了有效地进行采动巨厚湿陷性黄土地表裂缝损害的控制和治理，在对西部几个矿区开采地表裂缝破坏调查的基础上，应用概率积分法计算基岩顶界面的应力应变分布规律，分析其与地表裂缝的关系，研究开采引起黄土层地表裂缝产生的机理。

Applied overlay principle discloses intention at the complex load of break of grease wall of a well for individual and simple load, through set and time relevant aeriform pressure distributings function, rupture according to flexibility of stretch and mechanical, line condition of tie of stress of the upland after perforation of well of grease of mechanical and academic derivation plays factor of intensity of interstitial and most advanced stress, got deflagrating patulous condition is cracked since terrane of aeriform fracture wall of a well, the aeriform pressure gradient that this condition can follow time change inside reflective break is right the influence of interstitial configuration.

应用叠加原理将功能于油水井壁裂缝的复杂载荷分解为单个简单载荷，通过设定和时间相关的气体压力分布函数，根据弹性力学、线弹性断裂力学理论推导油水井射孔后高地应力约束条件下裂缝尖端应力强度因子，得到了爆燃气体压裂井壁岩层起裂扩展条件，该条件可以反映裂缝内随时间变化的气体压力梯度对裂缝形态的影响。

Aiming at irregularity of a real fracture surface or a real crack profile, applying Griffith's criterion and fractal geometry, the real asymptotic expression at the crack tip is developed, and it is discovered that the fractality of the crack reduces the stress singularity at the crack tip.

5针对实际断裂面或裂缝的不规则性，利用Griffith能量平衡原理及分形几何，推导了裂缝尖端实际应力场和位移场的表达式，研究发现，裂缝的分形性减小了裂缝尖端应力的奇异性。

In the process of building and using the mass concrete structures, because of the effect of out-side condition and themselves, some faults will form in the structure, these faults will effect the bearing capability and endurance Using nondestructive testing method to test the concrete"s quality and diagnose its healthy, which has the significant sense in assessing the safety stability and research of the administering diseasesThis dissertation mostly researched the testing methods in the mass concrete structure, discussed the principles, methods, features, sphere of application of the ultrasonic testing in the mass concrete structure with faults, used dynamic FEM to simulate the testing process, discussed when the concrete structure with cracks is under the effect of the pulse, how the elastic waves propagate and what are their changing feature, Researched the principles of the first-arriving waves" phase when the cracks" depths are not same, obtained the relation between the inversion point and the cracks" depth, which has the direction sense in the application of projects,The second part of this dissertation is CT , which used the ultrasonic wave running through the tested-substance to get arriving-time of the ultrasonic wave, then inverse the image This dissertation drawed one CT program which can well present the different little cells ultrasonic wave velocity profiles of the substance, thereby to diagnose the quality of the part of the tested-substance, CT has the better using foreground..

在混凝土结构的施工及使用过程中，由于受其自身及外界各种因素的影响，常常会产生一些缺陷，对结构物的承载能力和耐久性造成严重影响，采用无损检测技术进行质量检测和健康诊断，这对混凝土结构开展安全、稳定性评估以及病害隐患治理研究具有重要意义。本论文主要针对大体积混凝土结构缺陷的检测方法展开研究工作，重点讨论了超声波法检测混凝土结构裂缝的基本原理和方法及其特点、适用范围，运用动力有限元数值模拟其检测过程，探讨了有裂缝缺陷的混凝土结构在脉冲荷载作用下弹性波的传播及其变化特征，研究了不同裂缝深度下首波相位变化规律，得出了反转临界点与裂缝深度之间的关系，这对实际工程应用具有指导意义。声波CT是一种新的无损检测技术，它是利用声波穿透被检测体获取声波接收时间，来进行计算机反演成像的技术。本文利用直射线法编制了层析成像程序，能较好地呈现被检测物体各微小单元的声波速度分布图像，从而对检测体的质量状况作出诊断评估，具有较好的应用发展前景。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。