变水位静水法在渠道水利用系数计算中的应用

静水法是测验渠道渗漏水平、计算渠道水利用系数的试验方法之一,其测验精度高于动水法。尤其对于衬砌渠道,其测验精度更能得到体现。而变水位静水法是分析变动流量渠道水利用系数的适用方法。该文以水量平衡为依据,分析了渠道水利用系数的计算过程,以及当渠道水深变化时渠道水利用系数计算中相关因素的变化规律,并将渠道水利用系数计算过程概化为6步。以石津灌区四干三分干南四支混凝土衬砌渠道0+054~0+475渠段的变水位静水法和流量观测为实据,展示了衬砌渠道水利用系数的计算过程,计算水深介于0.56~0.99 m之间,渠道水利用系数为0.988~0.991之间。实例分析结果表明:随着渠道水深的增加,虽流量和渗漏强度均增加,但渠道水利用系数随水深呈增加趋势,该实例在水深大于0.7 m时,渠道水利用系数变化趋势渐趋平缓。可见,当渠道流量不稳定时,渠道水利用系数宜采用变水位静水法结合流量进行计算。     

Seepage Resistance and Moisture Proof of Concrete Using Electro osmotic Pulse

Seepage resistance and moisture proof of concrete structure is a hard work in civil engineering. The influence factors of seepage resistance and moisture proof of concrete using Electro Osmotic Pulse (EOP), such as electric voltage, water to cement ratio of concrete, ion concentration in liquid phase, and pulse frequency, were analyzed. Simulating experiment of EOP used to drain water and reduce relatively humidity of concrete structure is executed. The results show that, volume of water seepage is improved due to application of EOP in concrete with increase of electric voltage, W/C of concrete, and concentration of sodium sulfate. And pulse frequency has little effect on volume of water seepage. The results are also presented that effect of dewatering and humidity reducing are remarkable when EOP is applied in concrete structure.     

山区河道生态防洪堤关键问题及对策

根据山区河道的特点,探讨修筑生态防洪堤时的堤线布置、堤型选择、渗流及渗透稳定、河岸边坡整体稳定安全如何与堤防护岸的生态性有机结合等关键问题,结合充分利用当地材料修筑的生态防洪堤典型结构设计方案,提出了相应对策。     

洞庭湖区蓄洪垸堤防加固工程水土保持措施与设计优化

洞庭湖区地势平坦、土壤肥沃,现状水土流失强度轻微,但其堤防加固工程造成的水土流失影响仍不可忽视.总结了在堤防加固工程设计中,应重视的水土保持措施:包括土石方合理调配以尽量减少弃渣;选择合理的弃渣场,并因地制宜布置完善的拦挡、排水措施.同时,还从生态保护、节省投资角度,对主体护坡工程、堤基防渗工程提出优化设计建议,认为预...     

三维无压渗流分析的溢出面迭代法及其应用

全面考虑三维无压渗流问题中溢出面上的边界条件，将渗流自由面的确定问题转化为确定溢出面，同时结合使用渗透矩阵调整方法和丢单元技巧，给出了三维无压渗流问题的溢出面迭代方法。算例和工程应用表明该方法有效可行，而且具有较高的计算精度，最大误差为2．06％。     

ISS土壤固化材料在渠道防渗中的应用

ISS(Ionic Soil Stabilizer)土壤固化材料是一种新型的防渗材料。结合在广东湛江志满水库修建的ISS防渗试验渠道，介绍了ISS防渗技术的主要性能技术参数、施工工艺、施工要点和效益分析。应用表明：该技术防渗效果明显、施工简便、无污染、造价低，具有较好的推广应用前景。提出了存在问题及下一步的研究方向。     

土工膜防渗工程的渗流计算探讨

土工膜是一种新型防渗材料,在渠道、堤防、水库等防渗工程中已经得到了广泛的应用,但关于土工膜防渗工程的渗流计算方面还有待研究。基于土工膜的渗流机理,将发生在土工膜中的渗流分为土工膜本身渗透和土工膜缺陷渗漏两类,分别进行分析。根据原型观测资料进行反演,从平均意义上对土工膜的渗流系数进行取值,可以从宏观上解决土工膜缺陷难以确定的问题。最后分析了等效土体法进行土工膜防渗土石坝渗流计算的误差来源,指出在实际计算时,需要进行相应的误差分析。     

土坝渗透系数反分析方法研究

通过分析土石坝渗流的影响因素 ,分析渗透系数反演的二种情况 ,即单一区域渗流量有丰富的实测资料的情况和坝后总渗流量有实测资料的情况 ,并分别提出针对这二种情况的渗透系数反演方法     

Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

Soil water content is a key controlling factor for vegetation restoration in sand dunes. The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems. To determine the influence of vegetation on the hydrological regulation function of sand dunes, we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land, China. The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes. The accumulated deep seepage water of mobile dunes (vegetation coverage<5%) and dunes with vegetation coverage of 18.03%, 27.12%, and 50.65% accounted for 56.53%, 51.82%, 18.98%, and 0.26%, respectively, of the rainfall in the same period. The accumulated lateral migration of water in these dunes accounted for 12.39%, 6.33%, 2.23%, and 7.61% of the rainfall in the same period. The direction and position of the dune slope affected the soil water deep seepage and lateral migration process. The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope. The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope. According to the above results, during the construction of sand-control projects in sandy regions, we suggest that a certain area of mobile dunes (>13.75%) should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems. These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.     

较大孔径土工织物反滤特性对比研究

介绍了土工合成材料在辽宁省大洼三角洲应用于防洪护岸工程的情况。通过室内试验,对这种土工合成材料的物理力学特性、渗透性及反滤特性进行了试验研究。试验结果表明,非标准渗透仪可以代替标准渗透仪对防护工程进行试验研究。由于非标准仪尺寸大,更接近工程实际情况,所以可以更好地模拟工程条件,更具有对防护工程进行实验研究的实际意义。