引黄入晋北干线倒虹吸输水工程的水击压力控制

山西省万家寨引黄工程分成南干线和北干线.北干线倒虹吸输水工程全长113 km左右,采用内径2～2.2 m的PCCP管有压输水.研究了北干线倒虹吸输水工程的水击压力控制、调流阀安装位置对管道压力等级设计的影响及调流阀、泄压阀、检修阀的联合工作方式,以及设计了新型的多喷孔套筒调流阀以适应水击压力的控制要求.同时,也研究了该线路设计调压井或者溢流井的必要性及其参数.通过研究,不仅找出现有设计存在的安全隐患,提出了控制水击压力的工程措施,而且大大减少了工程投资.     

灰场土坝坝体变形及防治工程措施

山西阳坡灰场已加高至两级子坝,南坝肩为湿陷性黄土,且渗漏严重,现坝顶与坝肩均已产生裂缝.为加筑第三级子坝并防止现有病害的进一步发展,本文依据灰场大坝测压管、沉降和水平位移等原型观测资料,利用坝顶沉降倾度和坝顶拉伸,分析了坝顶及坝肩裂缝的成因与发展趋势,然后通过数值模拟,研究了第三级子坝加筑对当前变形的影响,最后结合监测分析与数值模拟的结果,针对不同类型裂缝提出了相应处理措施.本实例中,监测分析与数值模拟相结合的分析方法及裂缝的处理措施给类似工程项目提供了有益的借鉴.     

冲击弹性波法测试胶凝砂砾石性能的试验研究

本文简要介绍了冲击弹性波法的理论和特点,并采用此项技术针对胶凝砂砾石的力学强度,胶凝砂砾石坝保护层材料的抗冻耐久性能开展了探索性的试验研究。通过测试试件的波速与试件的力学强度和动弹性模量等建立相关联系,试验结果表明,抗压强度与弹性波波速存在良好的指数关系,动弹性模量与弹性波波速也具有较好的相关性。因此将此项技术应用到胶凝砂砾石筑坝工程的质量检测和安全监测方面具有前景,本文的室内试验成果为工程现场应用做出了初步探索。     

小水电工程项目经济评价实例分析

以耿镇水电站为例,根据业主决策需要,从国民经济评价和财务评价两个方面,对该小水电工程项目进行了计算分析。综合评价结果认为,该小水电工程项目的各项技术经济指标良好,该河段水能资源具有重要的开发利用价值。     

小水电工程项目经济评价实例分析

以耿镇水电站为例,根据业主决策需要,从国民经济评价和财务评价两个方面,对该小水电工程项目进行了计算分析。综合评价结果认为,该小水电工程项目的各项技术经济指标良好,该河段水能资源具有重要的开发利用价值。     

Use of bacterial cell walls as a viscosity-modifying admixture of concrete

This paper reports the rheological and other fresh properties of the cement paste amended with bacterial cell walls (BCW). The major component of BCW, peptidoglycan, resembles commonly used viscosity-modifying admixtures (VMAs) in chemical structures. Our results indicated that the apparent viscosities of the cement paste of W/C 0.36, 0.4, 0.44 and 0.5 amended with BCW of Bacillus subtilis were higher than those of the control cement without BCW. And the viscosities decreased with the increase of shear rates. BCW also increased the yield value of the cement paste. The VMA effects of BCW were comparable to that of diutan gum and dependent on the size of peptidoglycan, as lysozyme and sonication treatment decreased viscosities. BCW also demonstrated resistance to water dilution and resistance to bleeding and segregation. As an abundant material, BCW have the potential to be a new VMA in construction.     

渗水地膜全覆盖对高含盐土壤水盐运移的影响

为了提高旱作农田降雨的利用效率,解决高含盐土壤水分入渗及盐分淋洗效果等问题,在晋北应县进行了渗水地膜全覆盖土壤积水入渗试验。结果表明:高含盐土壤经过覆盖渗水地膜处理后的入渗量小于不做处理的土壤,且其入渗速度比较稳定,有利于积水均匀地下渗;在全覆盖渗水地膜的情况下,盐分运移的平衡点在40 cm深土壤处。通过渗水地膜全覆盖可有效降低高含盐土壤在0～40 cm土层的含盐量,并能保证耕层土壤的盐分淋洗效果。     

Effect of Moisture Content on Melilotus suaveolens Seed Quality During Ultra-drying Storage

In order to enhance the seed storability and supply high-quality seeds for vegetation restoration in the arid and semi-arid regions in Northwest China, the effects of ultra-drying and accelerated aging on the physiological characterstics of Melilotus suaveolens seeds were studied. Melilotus suaveolens seeds were dried in a desiccator containing silica gel to 80, 53, 42, 33, 23 and 16g·kg<'-1> of moisture contents (MC), respectively. The parameters of the seed quality including germination energy (GE), germination percentage (GP), relative conductivity (RC), dehydrogenase activity (DA) and a-amylase activity (AA) were determined afier ultra-drying and accelerated aging. The results showed that ultra-dried seeds with 42 g,kg-1 of MC showed the minimum changes of GE and GP before and after seed aging. Moreover, ultra-dry seeds with 42 g·kg<'-1> of MC showed higher DA and AA, and lower RC than non-ultra-drying seeds. Therefore, ultra-drying to 42 g·kg<'-1> of MC was helpful for M. Suaveolens seed storage.     

The combined finite–discrete element method for structural failure and collapse

A combined finite–discrete element model for failure and collapse of structural systems comprising of reinforced concrete beam or column type structural members has been developed and implemented into a combined finite–discrete element code. The results obtained using the proposed model compare well with analytical and experimental results. In addition the rotational capacities obtained are in good agreement with published experimental results.