水平裂缝对坚硬顶板失稳破断的影响规律研究

为了研究水力压裂形成水平裂缝后坚硬顶板的失稳破断规律,基于材料力学和关键层相关理论,结合数值模拟,对含水平裂缝坚硬顶板的变形破坏特征和失稳破断机制进行了研究。结果表明:当坚硬顶板存在水平贯穿裂缝时,无论上位与下位岩层是否发生同步运动,坚硬顶板的破断步距均小于其初始极限跨距。存在水平贯穿裂缝的坚硬顶板及其上覆岩层,会形成拉压复合破坏区,更易于发生失稳破坏。坚硬顶板块体咬合点区域的拉压复合破坏作用是造成块体局部失稳、回转加剧和整体破断的主要原因。     

考虑水平（切向）位移影响的垫层孔隙内土工膜顶胀

The common cushion layer used in the geomembrane face rockfill dam is made of granular materials such as gravel and non-fine concrete where bulge deformation or failure of geomembrane is very likely to occur in its surface holes. The curve intersection method based on the thin film theory is the common method used to analyze the bulge deformation of the geomembrane in the surface holes of cushion layer. However, it is inaccurate due to the neglection of horizontal (tangential) displacement of the geomembrane. Based on the FEM theory, a new method is proposed, which takes the horizontal (tangential) displacement of geomembrane into consideration, and is validated by the bulge tests on the geomembrane in a circular hole. The deformations and strains of the geomembrane in different shapes of holes are analyzed by this method, and different strain distributions and failure modes are obtained. The curve intersection method is also used to compare with the new method under the same condition. It is indicated that there is less difference in the deformation and average strain of the geomembrane when the water pressure is low. However, when the water pressure is relatively high, the influences of horizontal (tangential) displacement of the geomembrane on its strain should not be neglected.     

操作窗口对排风柜污染物控制效果影响的实验研究

为提升排风柜的控污能力,在排风柜性能测试实验台上,采用示踪气体测试法和正交试验法,研究了操作窗口竖直开度、水平开度、面风速和操作窗口位置对排风柜前呼吸区污染物控制效果的影响。极差分析和方差分析结果表明:各因素对呼吸区污染物控制效果影响的强弱顺序依次为竖直开度、水平开度、面风速、操作窗口位置;操作窗口水平开度、竖直开度增大,排风柜对呼吸区的污染物控制效果减弱;面风速增大,控制效果增强;水平开度与竖直开度对控制浓度的影响存在较大的相关性,这2个因素对控制浓度的影响仅在另一因素达到一定水平后才能体现。     

变厚度板中水平剪切波的传播特性分析

为研究超声导波在储罐壁板等变壁厚结构中的传播特性，建立了SH波在空间自由边界中的传播模型，基于各向同性弹性介质Navier-Stokes方程，推导了变厚度板中SH波的频散方程，分析了变厚度板中水平剪切波走时t与倾斜角θ间的相互作用关系；通过简谐点源的远场响应并引入板厚与传播位移的非线性关系，得出了变厚度板中SH波的远场响应方程。在此基础上，仿真分析和实验验证了水平剪切波在不同倾斜角变厚度板中的传播特性，结果表明：在变厚度板的薄端激励水平剪切波并沿结构表面传播时，无频散现象，且无波包分离现象；但随着变厚度板倾斜角θ增大，水平剪切波的走时和接收信号幅值均逐渐递减，且呈非线性关系。     

不同含量低污染水对人工湿地中细菌的影响研究

探究水平流人工湿地(HFCW)系统处理低污染水过程中,相同COD/ρ(TN)下不同碳氮含量对细菌群落结构的影响。结果表明,进水为较高碳氮含量的HFCW(HF1)和进水为较低碳氮含量的HFCW(HF2)对COD和TN的去除效率具有一定的差异,HF1和HF2对COD的去除效率分别为48.26%和28.89%,对TN的去除率分别为79.06%和81.87%。HF1中细菌的丰富度和多样性均高于HF2,HF1中富集的优势细菌为Chloroflexaceae、Comamonadaceae和Rhodocyclaceae,均具有异养反硝化功能,HF2中富集的优势细菌为Xanthomonadaceae和Rhodocyclaceae,其中Xanthomonadaceae具有自养反硝化功能。COD、NH4^+-N和NO3^--N对HF1中细菌群落的影响大于对HF2中细菌群落的影响,HF1中COD对细菌群落的影响大于NH4^+-N和NO3^--N。     

Heat transfer inside a horizontal channel with an open trapezoidal enclosure subjected to a heat source of different lengths

The heat transfer phenomena inside a horizontal channel with an open trapezoidal enclosure subjected to a heat source of different lengths was investigated numerically in the present work. The heat source is considered as a local heating element of varying length, which is embedded at the bottom wall of the enclosure and maintained at a constant temperature. The air flow enters the channel horizontally at a constant cold temperature and a fixed velocity. The other walls of the enclosure and the channel are kept thermally insulated. The flow is assumed laminar, incompressible, and two‐dimensional, whereas the fluid is considered Newtonian. The results are presented in the form of the contours of velocity, isotherms, and Nusselt numbers profiles for various values of the dimensionless heat source lengths (0.16 ≤ ε ≤ 1). while, both Prandtl and Reynolds numbers are kept constant at (Pr = 0.71) and (Re = 100), respectively. The results indicated that the distribution of the isotherms depends significantly on the length of the heat source. Also, it was noted that both the local and the average Nusselt numbers increase as the local heat source length increases. Moreover, the maximum temperature is located near the heat source location.     

压裂水平井产能预测方法研究进展

水平井压裂技术在低渗透及非常规储层中得到了广泛应用,压裂后水平井的产能预测关系到油田开发方案的制定,因此,国内外学者对压后渗流模型的建立和求解方法做出了不懈的努力。本文详细回顾了国内外学者所建压裂水平井产能预测模型及求解方法,指出了不同模型和求解方法的优缺点,并展望了压裂水平井产能模型的发展方向。     

两种串列方柱气动性能的试验研究

针对两种布置形式（水平布置和对角布置）的串列双方柱，通过同步测压风洞试验，在雷诺数为Re = 8.0×104、间距比为P/B = 1.75 ~ 5.00（其中P为方柱中心间距、B为方柱边长）条件下，得到了两种布置形式串列双方柱的表面风压，重点研究了对角串列双方柱的气动力、风压分布、Strouhal数等气动性能随方柱间距的变化规律，并与水平串列双方柱进行比较。水平串列双方柱的气动力在P/B = 3.00 ~ 3.50时会发生跳跃现象，下游方柱的平均阻力由负值突变为正值，而对角下游方柱平均阻力系数则均为负值。结果表明：当P/B<3.00时，对角串列双方柱的平均和脉动气动力系数、最大平均负压强度和脉动风压系数均大于水平串列双方柱，而当P/B > 3.00时则情况相反；对角串列双方柱的Strouhal数明显小于相同间距下的水平串列双方柱，且在P/B <3.00时对角串列双方柱的升力功率谱出现了多个峰值。     

扩孔钻头在水平定向井中的应用

传统扩孔钻头在长距离水平定向井应用过程中出现泥包问题时,由于钻速变慢易造成钻进轨迹偏离原井眼,而且起钻时由于抽吸压力对井壁的作用易造成井壁压差坍塌,影响井下钻具仪器安全,增加辅助时间和钻井成本。为解决该问题,通过总结施工经验,结合数值模拟理论实验优化改进扩孔钻头,并在山西某井田煤层气水平井钻井工程项目中进行工业性试验,与传统扩孔钻头相比平均钻时减少38.9%,大大减少辅助操作时间,钻进效率提高的同时减少钻井成本。     

开采过程中上覆复杂急倾斜构造岩层运移规律模拟研究

为了解开采过程中，急倾斜且具有水平裂隙发育的上覆岩层运移规律和特点，使用PFC3D软件建立该条件下的岩层模型，并进行了开采过程模拟。利用PFC3D中的JSET和Bonds模拟了非连续和连续性的岩体构造形式。模拟结果表明：上覆关键层下部始终不出现拉力，而是沿着急倾斜构造面产生裂隙，同时在开采面附近上覆成层岩体构造面存在较大的剪切错动，但整体仍然稳定。对开采过程产生的岩体最大颗粒位移量和地表最大沉降量进行定量分析，分别得到了这两个变量与走向方向推进长度的多项式函数关系。定量分析也证明了与模拟过程分析类似的结果。