浅表层及粗晶材料缺陷超声诊断方法

针对浅表层及粗晶材料,提出一种用小波变换与广义相关倒频谱分析相结合的缺陷诊断方法.该方法利用小波多分辨特性去除白噪声,利用广义相关倒频谱剔除始脉冲及材料散射噪声.实验结果表明:该方法提高了对浅表层及低信噪比缺陷的分辨力,缺陷诊断结果与实际结果相吻合,可用于浅表层及粗晶材料缺陷的诊断.     

近浅埋煤层大采高综采面矿压规律研究

霍洛湾煤矿所采煤层为近浅埋煤层,其22110工作面为一盘区第四个综采面,同时也是末采面,工作面赋存条件与接替的二盘区工作面条件及其相似,具体表现在煤层厚度、顶底板岩性、倾角、埋藏深度等。经对其进行矿压观测研究及支架适应性,得到工作面来压步距、过谷沟地形的矿压规律及支架工作阻力与动载系数,研究结论对二盘区安全高效开采具有现实指导意义,对可能存在的问题得以提前判知与解决。     

浅海环境中水下物体声目标强度的物理意义

根据简正波理论,推导了基于平均测量法的浅海环境中水下物体声目标强度TS（Target Strength）的解析表达式,深入分析了TS的物理意义.分析表明,在确定的方位角上,TS与分布在一定范围内的垂直入射角i和散射角s所对应的目标散射函数值有关,i和i是离散的,其取值取决于简正波阶数;同时,TS还跟海洋环境和测试距离有关,当测试距离非常大时,约等于自由场声目标强度TSfree.     

Analysis of mechanical behaviors of big pipe roof for shallow buried large-span tunnel

A series of researches on mechanical behaviors of big pipe roof for shallow large-span loess tunnel were carried out based on the Wenxiang tunnel in Zhengzhou -Xi＇ an Special Passenger Railway. The longitudinal de- formations of the pipe roofs were monitored and the mechanical behaviors of the pipe roofs were analyzed at the test section. A new double-parameter elastic foundation beam model for pipe roof in shallow tunnels was put for- ward in Wenxiang tunnel. The measured values and the calculation results agreed well with each other, revealing the force-deformation law of big pipe roof in loess tunnel： At about 15 m in front of the excavating face, the pipe roof starts to bear the load; at about 15 m behind the excavating face, the force of the pipe roof tends to be stabi- lized; the longitudinal deformation of the whole pipe roofs is groove-shaped distribution, and the largest force of pipe roofs is at the excavating face. Simultaneously, the results also indicate that mechanical behaviors of pipe roof closely relate to the location of the excavation face, the footage of the tunnelling cycle and the mechanics pa- rameters of pipe roof and rock. The conclusions can be reference for the design parameter optimization and the con- struction scheme selection of pipe roofs, and have been verified by the result of numerical analysis software FLAC3D and deformation monitoring.     

海上风电大直径宽浅式筒型基础抗弯特性分析

风机属于高耸结构物,承受巨大的弯矩是海上风电基础区别于其他常见结构基础的重要特征．大直径宽浅式筒型基础是适应海上风电特征荷载作用的新型基础型式．筒型基础的直径、入土深度、顸盖及侧壁厚度是控制其抗弯能力的重要技术参数．结合某海上风电工程实例,采用数值分析方法,系统研究了不同尺寸特征参数对筒型基础传递及抵抗弯矩荷载的影响,揭示了弯矩荷载作用下宽浅式筒型基础的失效模式及基础转动点位置;研究了地基承载力设计中等效均质算法的合理性．研究表明：基础抗弯承载能力随筒型基础的直径及入土深度的增加而显著增长;在弯矩荷载作用下,筒周围土体出现贯通的弧形破坏面而在基础下方土体中存在曲边三角形的稳定区;对于实际工程中的上软下硬成层土地基,经等效均质化后,将导致计算得到的基础抗弯极限承栽力明显偏高．     

环形浅液池内双组分溶液耦合热溶质毛细对流渐近解

采用匹配渐近展开法求解环形浅液池内热溶质耦合毛细对流中心区域渐近解,分析Soret效应和浮力对流动的影响。结果表明,当不考虑溶质毛细力和浓度的不均匀引起的浮力作用时,该解与环形浅液池内纯工质热毛细浮力对流或热毛细对流的渐近解完全一致;在浅液池内,浮力的影响较小,耦合的热溶质毛细力对流动过程起主导作用;当各种耦合的驱动力作用方向相同时,流动加强,相反,一旦存在反向的情况,则流动必然相互削弱。     

基于小振幅机械波动方程的水面模拟

自然水面模拟在计算机游戏和影视等行业中有重要的应用.已往基于物理的水面模拟大都通过求解复杂的NS(Navies Stokes)方程来实现.为了降低计算的复杂性,提高模拟的效率,根据弦受力运动过程,通过适当的假设,推导出小振幅机械波动微分方程.通过求解此方程来进行水面波浪模拟,并利用水面光学特性,加强水面真实.实践证明,算法成功地实现了水面的模拟,取得了很好的模拟效果,避免了复杂的求解过程,算法运行效率很高.     

淮河流域典型闸坝断面的生态综合评价

为分析淮河流域的闸、坝等水利设施对水生态环境的影响,采用多种生物指数法对淮河流域典型闸坝断面的生态系统现状进行了综合评价。结果表明,大多数水库处在生态稳定的健康状态;64%的所调查评价的河流生态系统处在不健康或亚健康状态。淮河干流水生态与水环境优劣的突变点在临淮岗,临淮岗以上的河段污染较轻;临淮岗以下河段污染较重。建议统筹考虑流域闸坝间水量联合调度与水污染源控制的共同作用,以使淮河流域水生态尽快得到恢复改善。     

考虑断层影响的煤层开采沉陷三维有限元模拟

为了解决山东某煤矿的煤层开采对周边俱乐部沉降的影响问题,采用有限元分析的方法并建立不同开采方案的三维地质模型,同时考虑断层的影响,计算出煤层开采后俱乐部四角的地表下沉状况。研究结果表明:回采3101工作面时俱乐部地表下沉最大值达到382 mm,因此建议对俱乐部进行加固保护处理。该成果为研究最佳开采方案及周边俱乐部的保护提供重要依据,同时为浅埋煤层以及类似条件下中小矿山合理、安全、经济的开发提供了重要的参考依据。     

The design of Three Gorges Hydropower Station

Using physical model and numerical simulation techniques,some technical problems were studied systematically,including layout of power station,measures of sediment and floating debris discharging,types of intake,embedded types of spiral case,layout of underground powerhouse tunnel group and block reinforcement.It was optimal in technique and economy with the arrangement of powerhouse at the dam-toe of both banks +underground powerhouse in the right bank,as well as the intake with a single and small orifice.The sediment and debris problems could be solved with disperse sediment ejection and floating debris discharging holes.With the adoption of techniques for spiral cases such as heat and pressure preservation,cushion layer and combined embedding,the stable operation of generating units can be guaranteed.The arrangement of tailrace tunnel with sloping ceiling was better than that of tailrace surge tank.The technical requirements related to the embedding type of spiral case were proposed.The reinforcement of huge unfavorable blocks was discussed and the new idea for block reinforcement using anti-sliding piles and normal compressive stress of structural plane was put forward.