用土工织物滤层处理渠堤管涌

一、险情湖南益阳县明星电排站地处洞庭湖滨资水左岸的防洪大堤脚下。这一装机为3×155kW的外排机埠于1977年建成,担负着1.25万亩农田的排涝任务。泵站引水渠底宽6m,边坡比1:2,最高水位3.5m,设计流量4.7m^3/s。站址及渠首位置由一深潭逐渐淤积而成,砂卵石埋置浅。

滨海盐渍土原土滴灌水盐调控对土壤水力性质的影响

为研究滨海盐渍土滴灌原土水盐调控不同处理对土壤导水率(K)、土壤孔隙大小分布常数(Gardnerα)、土壤孔隙对水流贡献率等水力性质的影响,在滨海盐渍土上进行滤层及基质势(-5、-10、-15、-20、-25kPa)处理的原土水盐调控试验。用圆盘入渗仪在-15、-6、-3、0cm4个连续增大的负压下进行入渗测定,并计算不同负压下导水率、土壤孔隙大小分布常数、孔隙级别对水流的贡献率。结果表明:经原土水盐调控后,各处理的饱和导水率、土壤孔隙大小分布常数较对照增大,在-6和-15cm水头下的导水率较对照减少,在-3cm水头下的导水率无明显变化规律。滤层处理下土壤的饱和导水率、-6cm水头下的导水率、土壤孔隙大小分布常数较无滤层处理有显著提高;各处理土壤大孔隙对水流的贡献率大于对照处理,中等孔隙2及小孔隙对水流的贡献率小于对照处理。滤层处理是不同级别土壤孔隙对水流贡献率大小的主要影响因素,其中滤层的土壤大孔隙、中等孔隙1对水流的贡献率显著高于无滤层。可见,经原土水盐调控后,土壤饱和导水率、-6cm水头下的导水率、土壤孔隙大小分布常数明显增加,土壤大孔隙增加,小孔隙减少,土壤结构得到改善。

Co-flocculation mechanism and physical model

Analysed and summarized the dynamics and chemical factors in the co (co-agulation)-flocculation process. A completely new definition for co-flocculation was given. If a colloid particle didn抰 contact with drug to emerge (physical) chemical effect, the possi-bility for the colloid particle to coagulate (flocculate) was rather small, only at the floccula-tion stage; it may be caught by net or settled by differential sedimentation. Base on sev-eral assumed important premises, the several steps and physical model of co-flocculation process were given, and the mixing, coagulation and flocculation were proposed accord-ing to their essentiality.