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71.
72.
The stochastic nature of the cyclic swelling behavior of mudrock and its dependence on a large number of interdependent parameters was modeled using Time Delay Neural Networks (TDNNs). This method has facilitated predicting cyclic swelling pressure with an acceptable level of accuracy where developing a general mathematical model is almost impossible. A number of total pressure cells between shotcrete and concrete walls of the powerhouse cavern at Masjed–Soleiman Hydroelectric Powerhouse Project, South of Iran, where mudrock outcrops, confirmed a cyclic swelling pressure on the lining since 1999. In several locations, small cracks are generated which has raised doubts about long term stability of the powerhouse structure. This necessitated a study for predicting future swelling pressure. Considering the complexity of the interdependent parameters in this problem, TDNNs proved to be a powerful tool. The results of this modeling are presented in this paper. 相似文献
73.
使用可控震源应注意三方面的问题:一是与大地的耦合,二是参数的最佳选取,三是在保证野外采集工作量近似不变情况下,提高地震剖面质量。解决方法是:配备可控震源力控装置、改变表层介质波阻抗可消除震源脱耦现象;选取参数应考虑清晰度、分辨率、信噪比,避免虚像出现在有效记录范围内;在野外数据采集时应减少振动次数、增加覆盖次数并注意压制不规则干扰和噪声,以提高地震剖面质量。 相似文献
74.
为治理龙庞矿陷落柱实水事故,采用螺杆钻进技术在陷落柱南缘设计施工两个定向井Z5-1及Z5—2。以Z5-1定向井为例,使用Ф117.6mm钻头,采用优质化学泥浆,钻压35~40kN,随钻钻进至480m后改为回转钻进,在稳斜钻具钻到516.45m处进行水泥浆堵漏,边堵漏边钻进,并且每钻进10m左右测斜一次,直到中靶。 相似文献
75.
在论述了瓦斯地质钻探目的和非平衡钻探工艺理论的基础上,总结了瓦斯地质钻探施工工艺及相关技术措施并强调了安全施工要求。 相似文献
76.
SUN Bainian XIAO Liang XIE Sanping DENG Shenghui WANG Yongdong JIA Hui Susan?Turner 《《地质学报》英文版》2007,81(6):931-939
A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant physiology since the 1980s has led to the realization that fossil plants can serve as a proxy for paleoatmosphere and paleobiosphere. As a relict gymnosperm with evolutionary stasis, Ginkgo is well suited for paleoenvironmental reconstruction. This paper analyzes fossil Ginkgo species from integrated strata in the north of China using anatomic data of plant physiology. Using stomatal parameters, a trend for the paleo-CO2 level during the Early-Middle Jurassic and the Early Cretaceous was obtained, which is consistent with the estimates by GEOCARB. The trend is also similar to that of Mean Global Surface Temperature in geological time. Compared with three other atmospheric CO2 concentration parameters, the trend of paleo-CO2 level based on the stomatal parameter of the fossil Ginkgo specimens from three contiguous strata is more exact. 相似文献
77.
云驾岭矿区上部黄土中夹杂大量卵砾石,下部地层则因岩浆岩侵入具有岩硬、破碎、漏水、掉块等特性,严重影响钻进效率。为克服卵砾石及硬岩钻进难题,选用多工艺液压钻机YHJ-2000及性能参数比较稳定1150-XH空压机等钻探设备。采用牙轮钻头钻进、气动潜孔锤以及金刚石复合片等复合钻进工艺,并根据地层岩性确定钻孔结构、钻具组合及钻进参数。施工中注意调整泥浆性能,保证泥浆携带岩粉能力。经实践验证,该区采用的钻进工艺和方法,有效地提高了钻效,达到500m/月。 相似文献
78.
钻井液流变性是钻井液流动和变形的特性,对于携带与悬浮岩屑、提高钻进速度至关重要,准确掌握钻井液流变参数是保证井眼清洁与高效钻进的前提。提出一种基于卷积神经网络(Convolutional Neural Network,CNN)的钻井液流变参数智能识别方法,通过磁力搅拌产生稳定的钻井液流动图像,利用多种数据增强方法增加图像数量并建立数据库,增强模型的鲁棒性和泛化能力。优化AlexNet卷积神经网络算法,构建钻井液流变参数识别模型。将数据库划分为训练集:验证集:测试集=7:2:1,对训练集进行迭代训练并通过验证集调整参数获得最佳拟合模型。此外,运用混淆矩阵、卷积核可视化技术和类激活技术(Gradient-weighted Class Activation Mapping,Grad-CAM)对模型进行多方位评估。结果表明:(1)钻井液流变参数识别模型对钻井液塑性黏度测试的宏精确率为95.2%,宏召回率为94.7%,宏
79.
Impulsive force of debris flow on a curved dam 总被引:8,自引:0,他引:8
Although Sabo dams are an efficient method for river and basin management, traditional Sabo dams have a great impact on ecology and landscape. Moreover, such dams are hit and often damaged by great impulsive force when they block the debris flow. Therefore, alternative shapes for Sabo dam deserve thorough investigation. In this investigation, a curved dam was designed by changing the upstream-dam-surface geometric shape to reduce the impulsive force of the debris flow, with enhanced stability and reduced concrete mass being the anticipated outcomes. In this study, the flume and laboratory facilities simulated the impulsive force of the debris flow to the Sabo dams. Three geometric forms, including vertical, slanted and curved Sabo dams, were used to determine the impulsive force. Impulsive force theories of the debris flow were derived from the momentum equation and the Bernoulli equation. In these, the impulsive force was balanced by the friction force of the Sabo dam and the opposite force of the load cell behind the dam as it was hit by the debris flow. Positive correlations were found when comparing the experimental data with the theoretical results. These findings suggest that our impulsive force theory has predictive validity with regard to the experimental data. The results from both theory and experimental data clearly show that curved darns were sustained less force than the other darns under the same debris flow. This comparison demonstrates the importance of curved geometry for a well-designed Sabo dam. 相似文献
80.