对利用中子测水技术测定非饱和带参数的探讨

本文通过野外实践 ,总结了中子测水技术测定非饱和带持水度和给水度的方法 ,该方法直接、简单、准确 ,具有推广价值。

Effect of Mulberry(Morus alba Linn) on Soil and Water Conservation

Rational development and utilization of hilly land is an effective measure for raising land productivity, developing countryside economy, increasing peasants＇ income, conserving soil and water, and improving eco-environment. The growth and root distribution of mulberry trees were studied. Various indexes including soil physical characters and hydrological status, water infiltration rate, water and soil loss and soil erosion amount were tested. The results indicated that mulberry trees had the effects of intercepting rainfall, improving soil infiltration rate, decreasing soil erosion amount, and conserving water and soil

对舒兰含煤地层含水流砂的浅见

廿几年来,舒兰矿对防治流砂水作了许多工作。摸清了该矿流砂产生的原因,运动状态以及地下水运动的关系,并找到了防砂疏水的一些方法,取得了一定效果。

填埋场排水层渗透性演变模拟研究

渗滤液在排水层渗透过程中会使排水层的渗透性降低。通过室内模拟试验,研究了在渗滤液渗透作用下排水层渗透性的演变规律,特别是排水层持水度、渗透系数、淤堵物特性间的关系及变化特征。研究结果表明:渗流初期是淤堵物与持水度的快速增长期,而排水层渗透系数的主降期要比前者长;淤堵物与持水度的增长对排水层渗透性的影响具有滞后性;渗流时间影响淤堵物的生成量,但不影响各元素的百分含量。该成果对于填埋场渗漏防治具有借鉴意义。

Effect of temperature on soil-water characteristics and hysteresis of compacted Gaomiaozi bentonite

Laboratory tests under different constraint conditions were carried out to obtain the soil-water retention curves(SWRCs) of highly-compacted confined/unconfined Gaomiaozi(GMZ) bentonite at 20,40 and 80 ℃,respectively. The effect of temperature on the soil-water characteristics of the highly-compacted GMZ bentonite was analyzed. The results show that the water retention capacity of the highly-compacted GMZ bentonite decreases as the temperature increases under unconfined and confined conditions. At a certain temperature,the constraint conditions have little influence on the water retention capacity of the compacted bentonite at high suction,but the water retention capacity of the confined specimen is lower than that of the unconfined specimen at low suction. Under unconfined conditions,the hysteretic behaviour of the compacted bentonite decreases with increasing temperature. At high suction(>4 MPa) ,the hysteretic behaviour of the unconfined bentonite tends to increase with the decrease of the suction. In summary,the hysteretic behaviour of the compacted bentonite is not significant.

SEDIMENT TRANSPORT IN YALU RIVER ESTUARY

Tidal cycle measurements of tidal currents, salinity and water tempe rature, and suspended sediment concentrations were measured at four stations, to gether with surveys along two profiles short core collection within the Yalu Riv er estuary. Grain size analysis of the three core sediment showed that: 1) the s ediment from B1 to B3 became finer, worse sorting and positively skewed; 2) the diversification of matter origin became more and more evident from east to west; 3) the sediments over the region were of the same origin, as indicated by their similar colors and grain sizes. The data indicated that stratification occurred in the flood season, from upstream to downstream, and a salt wedge was formed. The water column was well mixed, but the longitudinal gradient of the salinity w as larger on spring tide. The results also showed that the dominating mechanism of suspended sediment transport in the Yalu River estuary was T1, T2, T3 and T5. The non-tidal steady advection transport was restricted by the net transport o f suspended sediment induced by mass Stoked drift directed to landwards, then th e net sediment transport rate were decreased and the turbidity maxima was also f avored to forming and extending.

Integrated assessment model of water resources constraint intensity on urbanization in arid area

Water has become a key restricting factor of the urbanization process in developing arid areas.Based on qualitative and quantitative methods,we constructed an integrated in-dicator system to assess the status of water resources and urbanization system in arid area,and established an AHP model reformed by entropy technology to evaluate the temporal and spatial variations of water resources constraint intensity on urbanization.This model is ap-plied to the Hexi Corridor,a typical arid area in NW China.Results show that,water resources constraint intensity on urbanization in the Hexi Corridor is bigger in the east and smaller in the west.It has changed from the less strong constraint type into the strong constraint type from 1985 to 2005,yet it decreased appreciably in recent years.At present,most areas in the Hexi Corridor belong to the less strong or strong constraint type.Through rational adjustment of water resources and urbanization system,the Hexi Corridor can still promote water resources sustainable utilization and accelerate the urbanization process.This study suggests that the integrated assessment model of water resources constraint intensity on urbanization is an effective method to analyze the conflicts between water resources and urbanization system in arid area.

Coupling relation between water and salt in irrigation area on a catchments scale

Water resource is the important factor for sustainable development in Weigan River catchments in western China. Based on ecological hydrology principles, the coupling relation between water and salt is monitored and analyzed. The water quality for irrigation in oasis ecosystem has a larger variable range in arid area, which depending on the input water resource and underground water mineralization degree and water chemical component on the catchments scale, the water and salt coupling is decided by the climate condition and soil feature and vegetation characteristics as well as human activity. Meanwhile, temporal and spatial change between water and salt is quite complicated. The environmental management should be paid attention to considering in irrigation area in the catchments.

Determining the Optimum Inflow Rates for Micro-flood Irrigation on the Tukulu Soil

The performance of micro flood irrigation （MFI） under different inflow rates was evaluated on 90 m closed ended furrows in the South African Tukulu soil. A single irrigation was used to characterise the surface and subsurface soil water distribution from the 20, 40, 80 and 160 L/min inflow rates treatments. Neutron access tubes were installed to a depth of 1 m at every 10 m distance interval starting at 5 m from the furrow inlet. Soil water content measurements were taken using the WaterMan neutron water meter. The HYDRUS-2D software was also used to provide insight on irrigated furrows soil water content and subsurface water distribution. The 20 L/min produced a stream flow that could advance up to the 60 m furrow distance. The stream flow from the rest of the inflow rates were able to reach the furrow end with the 180 L/min recording the fastest advance time of 23 min. The 20 L/min and 40 L/min had recession period of less than 7 min while the 80 L/rain and 160 L/min lasted more than an hour. Distribution uniformity （DU） at longer furrow distances was the highest from the 80 L/min and 160 L/min with the 20 L/min and 40 L/min recorded similar performances at shorter distances. The 40 L/rain was one of the smaller inflow rates that recorded the highest DU of 0.96 for the generated average infiltrated depth of the 30 m long furrow and therefore should be adopted for furrow distances of less than 60 m on the Tukulu soil.

High-Volume Fly Ash Concrete-A Relevant Step to Sustainable Development

HVFA （high-volume fly ash） concrete could be a sustainable way for by-product utilization to conserve natural resources and protect environment. HVFA concrete can play the role of a high-performance material that may be comparable to the conventional Portland cement concrete. The results of the research programme concerning the relationships between the composition of concrete （w/b ratio, fly ash content and type of cement） and their physical and mechanical properties are presented and discussed in the paper. It is found that the introduction of high-volume fly ash into concrete has caused a decrease in compressive strength at the early age of storage. The significant increase in strength was observed between 28 days and 90 days of curing. The high-volume fly ash concretes were characterized with lower water absorbability and sorptivity than control concrete.

Performance evaluation of fly ash-copper slag-based geopolymer bricks

This study investigates the production and evaluation of geopolymer bricks made from a blend of fly ash,copper slag,soda ash activator,and sand as fillers.Locally abundant industrial and mining waste materials were selected as the primary components.The bricks were synthesized using two binders:60%fly ash with 40%copper slag,or 70%fly ash with 30%copper slag.Both were milled with the activator at a 0.2 soda ash-to-precursor ratio.Fine sand was added to the mixes at 1:2 and 1:3 binders-to-sand ratios.The bricks’physical,mechanical,and durability properties were examined through compressive strength,modulus of rupture,density,water absorption,drying shrinkage,and efflorescence test,and their performance was compared to established industry standards.The experimental findings indicate that bricks made with 60%fly ash,40%copper slag,and a 1:2 binder-to-sand ratio exhibited optimal compressive strength(9.64 MPa)and water absorption(7.5%)at 28 days of curing age.Conversely,there was only a marginal increase of up to 4.7%in the strength of the formulation with 70%fly ash and 30%copper slag,attaining a compressive strength of 4.9 MPa between the curing ages.Furthermore,the results indicated a positive correlation between the density and compressive strength of the geopolymer bricks at similar curing ages.The bricks’density showed minimal variation with curing age and the highest modulus of rupture value observed was 2.5 MPa.The optimal bricks also exhibited relatively low linear shrinkage,good resistance to efflorescence,and met the relevant industry standards.

Long-term precipitation change by hourly data in Haihe River Basin during 1961–2004

Hourly summer precipitation data recorded at 21 stations during 1961-2004 in the Haihe River Basin in North China were an alyzed. The results show that the precipitation frequency and amount and the morning peak mainly relating to longduratiol rainfall events decreased during this period, whereas the normalized afternoon peak mainly relating to short-duration event： increased, which may suggest that the proportion of short-duration rainfall has increased as the total summer rainfall has de creased. For short-duration events, the mean intensity and peak intensity increased at most stations and the time to peak inten sity decreased, which may be attributable to the higher thermal contrast between the warmer lower surface and cooler uppe level. In the case of long-duration events, the total amount was significantly correlated with the East Asian summer monsool index for the period 1961-2001 （correlation coefficient of 0.63）. Although the total amount of rainfall in long-duration event： decreased in the basin, the mean intensity and peak intensity, as well as the extreme hourly precipitation, increased in the western basin and decreased in the eastern basin.