裂缝性地层黏弹性地震多波波动方程

裂缝检测是目前国内外石油勘探界研究的一个热点问题，如何确定裂缝方位等参数是石油公司面临的难题，而解决该难题就要确定裂缝方位等参数与地震波场传播之间的定量关系.但是目前所采用的裂缝性地层介质模型不能完全定量地反映裂缝的方位特征和衰减特征.针对该问题，建立了具有任意裂缝方位的裂缝性地层介质模型；并构造了时间增量的方法，将非线性的卷积积分采用近似的方法实现，建立了以位移场表示的具有任意方位角的黏弹性方位各向异性介质的波动方程.该波动方程定量地给出了黏弹性波场特征与裂缝走向的关系，描述了黏弹性地震波在这种介质中的 关键词： 裂缝 各向异性 黏弹性 波动方程     

中国现代珠算史料

六、中国珠算协会成立大会 中珠协筹备工作开展顺利，各省也发展很快，中国珠算协会已到非正式成立不可的时候了。姜明远同志已接受担任会长一职，并亲自到中国科协学会部商量，征得支持，拨1万元作大会经费。一切具备，可以说是水到渠成。会址选在河北省秦皇岛市，定于1979年10月31日至11月5日为开会日期。     

吉林省珠算协会是如何持续开展珠心算普及教育工作的

吉林省珠算协会成立于1980年。25年来,在吉林省财政厅党组高度重视和正确领导下,在中国珠算协会的具体指导下,在各级财政、教育部门、各级珠协和广大一线珠心算教师的配合支持和辛勤耕耘下,全省珠心算普及教育工作取得令全国瞩目的成就。下面,就吉林省如何持续开展珠心算普及教育工作的经验介绍如下:     

现浇板裂缝产生原因及对策

结合工程事故的实例，分析了现浇板常见裂缝产生的原因，提出了裂缝控制的建议．     

考虑横缝、裂缝接触非线性的高拱坝抗震分析

高拱坝横缝、裂缝在地震作用下对坝体的影响不可忽略.通过采用局部连续-非连续变形动态接触算法,考虑横缝、裂缝接触非线性,无限地基的辐射阻尼效应,以及坝体-库水的相互作用,对某高拱坝抗震性能进行了分析,结果表明:上游坝面的拱冠梁附近及左右岸坝肩附近的横缝开度较大;下游坝面左岸坝肩靠近拱冠位置的横缝开度较大;裂缝B比裂缝A的...     

Application of scaled boundary finite element method in static and dynamic fracture problems

The scaled boundary finite element method (SBFEM) is a recently developed numerical method combining advantages of both finite element methods (FEM) and boundary element methods (BEM) and with its own special features as well. One of the most prominent advantages is its capability of calculating stress intensity factors (SIFs) directly from the stress solutions whose singularities at crack tips are analytically represented. This advantage is taken in this study to model static and dynamic fracture problems. For static problems, a remeshing algorithm as simple as used in the BEM is developed while retaining the generality and flexibility of the FEM. Fully-automatic modelling of the mixed-mode crack propagation is then realised by combining the remeshing algorithm with a propagation criterion. For dynamic fracture problems, a newly developed series-increasing solution to the SBFEM governing equations in the frequency domain is applied to calculate dynamic SIFs. Three plane problems are modelled. The numerical results show that the SBFEM can accurately predict static and dynamic SIFs, cracking paths and load-displacement curves, using only a fraction of degrees of freedom generally needed by the traditional finite element methods.The project supported by the National Natural Science Foundation of China (50579081) and the Australian Research Council (DP0452681)The English text was polished by Keren Wang.     

Discussion on electromagnetic crack face boundary conditions for the fracture mechanics of magneto-electro-elastic materials

This paper discusses electromagnetic boundary conditions on crack faces in magneto- electroelastic materials, where piezoelectric, piezomagnetic and magnetoelectric effects are coupled. A notch of finite thickness in these materials is also addressed. Four idealized electromagnetic boundary conditions assumed for the crack-faces are separately investigated, i.e. (a) electrically and magnetically impermeable (crack-face), (b) electrically impermeable and magnetically permeable, (c) electrically permeable and magnetically impermeable, and (d) electrically and magnetically permeable. The influence of the notch thickness on important parameters, such as the field intensity factors, the energy release rate at the notch tips and the electromagnetic fields inside the notch, are studied and the results are obtained in closed-form. Results under different idealized electromagnetic boundary conditions on the crack-face are compared, and the applicability of these idealized assumptions is discussed.The project supported by the National Natural Science Foundation of China (10102004) The English text was polished by Yunming Chen.     

基于数字图像处理技术的不同岩性岩石裂缝动态演化规律的实验研究

为了解喀喇昆仑公路(中国段)部分区域岩石力学性能,采用数字图像相关技术,对采集的不同岩性岩石,在三点弯曲和单轴压缩的载荷作用下,进行了岩样位移场、裂缝起裂、扩展等动态演化规律的实验研究.通过定量和定性分析,得出了裂纹演化及路径因岩石种类不同有所区别,三点弯曲岩样裂纹发生部位在受拉应力一侧,单轴压缩试件在边角处局部压溃导...     

砂粒与复杂流体压裂液在裂缝中的流动特性研究

在矩形裂缝通道中,应用高速摄像技术,研究了复杂流体压裂液水平流动过程中砂粒的沉降速度,测试了复杂流体的流变学特性,分析了复杂流体的水平流动如何影响砂粒的沉降.研究结果表明,流性指数不等于1的复杂流体,其水平流速影响砂粒的沉降规律,砂粒在裂缝中水平流动过程的沉降速度不仅随复杂流体表观粘度的减小而增大,同时随复杂流体水平流速的增大而增大,是静止沉降速度的数倍至十数倍.     

水溶性AM-AA-NVP-AMPS-PDE暂堵剂的合成与性能

以丙烯酰胺、丙烯酸、N-乙烯基吡咯烷酮、2-丙烯酰胺基-2-甲基丙磺酸、1,5-戊二醇二丙烯酸酯为主要原料,制备了AM-AA-NVP-AMPS-PDE五元共聚物暂堵剂(本产品)。采用红外光谱以及元素分析对该暂堵剂结构进行了表征,研究了该暂堵剂的抗剪切性能、耐盐性能、悬浮性能、降解性能以及暂堵性能。实验结果表明,与常规暂堵剂AM-AA-MA相比,本产品具有更强的抗剪切强度、更高的膨胀倍数;在相同质量浓度氯化钠溶液中,本产品的抗剪切强度、膨胀倍数均高于AM-AA-MA。本产品吸水膨胀后,在压裂液中具有较好的悬浮稳定性能。本产品的降解时间受温度影响,在80℃下完全降解需要46.2h,所得溶液的黏度为1.9mPa.s;在120℃下完全降解需要1.8h,所得溶液的黏度为1.8mPa.s。本产品具有较强的封堵能力,抗压强度为15.8MPa,不需外加破胶剂即可在温度和水的作用下实现解堵,对应的渗透率恢复率为96.1%。