外载荷作用下排土场的稳定性

矿山生产中,在外载荷作用下排土场稳定性的破坏可能造成滑坡灾害及非生产物质消耗。根据相似材料模拟分析结果制定了试验方法。相似材料采用混合材料1(石英砂、石子、润滑油)和混合材料2(石英砂、粘土、石腊)。混合料1是用于模拟松散泥质的各种风化岩,其容重γ=1.8～2.5g/cm^3。

Physical simulation test of soil-rock mixture from synthetic transparent soil

The waste dump of open-pit coal mine is remade of soil-rock mixture under the action of gravity,dynamic load of transportation equipment and earthquake,etc.By using artificial synthetic transparent soil,the developing process and migration law for soil-rock mixture are observed in the remade process.The mixture of fused quartz sand,liquid paraffin and n-tridecane is chosen as the material for synthetic transparent soil which is mixed with liquid paraffin and n-tridecane at a mass ratio of4.4at room temperature of17℃.Physical and mechanical properties of transparent soil are determined by physical test and compared with those in natural sandy soil.The results show that transparent soil and sandy soil have high similarity,in other words,transparent soil can be used for similar simulation experiments of soil-rock mixture.

Natural vegetation recovery on waste dump in opencast coalmine area

The changes of vegetation compositions, plant species diversity, species important value and succession of plant community were studied on waste dumps in Haizhou opencast coalmine which is located in the west of Liaoning Province, China (41°41(-42°56( N, 121°1(-122°56(E). Four kinds of terraces with different ages (5, 10, 20 and 40 years) were selected for investigation of plants. Total of 63 species of natural colonized plants were recorded on the waste dump and they belong to 23 families. The main families were Compositae (15 species), Fabaceae (11 species) and Leguminosae (8 species), which accounted for 54.0% of total species and play an important role in natural vegetation recovery in waste dump area. The dominant species on 5-, 10-, 20-, 40-year-old terraces were Tribulus terrestris + Echinochloa hispidula + Salsola collina, Echinochloa hispidula + Artemisia sieversiana + Artemisia scoparia, Echinochloa hispidula + Clinelymus dahuricus + Artemisia scoparia + Artemisia sieversiana + Melilotus officinalis, Clinelymus dahuricus+Phragmites communis + Echinochloa hispidula+ Setaria viridis, respectively. According to the important value of species calculated. It is determined that Tribulus terrestris can act as pioneer species on waste dump and Clinelymus dahuricus, Phragmites communis and Echinochloah hispidula are important dominant species in vegetation restoration in Haizhou opencast coalmine. The study results can provide scientific basis for selecting and disposing appropriately plant species and rehabilitating vegetation on waste dumps of coalmine.

Effect of barley straw biochar application on greenhouse gas emissions from upland soil for Chinese cabbage cultivation in short-term laboratory experiments

Chinese cabbage was cultivated in upland soil with the addition of biochar in order to investigate the potential for reduction of greenhouse gas emissions. Barley straw biochar(BSB) was introduced in a Wagner pot(1/5000a) in amounts of 0(BSB0, control), 100(BSB100), 300(BSB300), and 500(BSB500) kg 10a^(-1). After the addition of BSB into the upland soil, carbon dioxide(CO_2) emission increased while methane(CH_4) and nitrous oxide(N_2O) emissions decreased. The highest CO2 flux was measured for the BSB500 sample,(84.6 g m^(-2)) followed by BSB300, BSB100, and BSB0 in decreasing order. Relative to those of control, the total CH_4 flux and N_2O flux for the BSB500 treatment were lower by 31.6% and 26.1%, respectively. The global warming potential(GWP) of the treatment without biochar was 281.4 g CO_2 m-2 and those for treatments with biochar were in the range from 194.1 to 224.9 g CO_2 m^(-2). Therefore, introducing BSB into upland soil to cultivate Chinese cabbages can reduce the global warming potential.

Response of N_2O Emissions of Farmland Ecosystem on Temperature Rising

[Objective] The aim was to study on response of N2O emissions of farm- land ecosystem on temperature rising. [Methed] In farmland ecosystem in Huaibei City in Anhui Province, N2O emission by twelve varieties of crop on temperature was researched with DeNitrification-DeComposition （NDC）. [Result] Response of dry- land crop on temperature rising can be divided into three categories, as follows： The first category, N2O emission of crop changed little during the temperature increasing, for example, from 0 to 3 %;, the emissions by potatoes, cotton, maize and rapeseed increased little and decreased little when temperature changed from 1.5 to 3 ℃. Crops of the second category declined with temperature increasing in N2O emission, for example, N2O emission decreased by 8.1% with temperature increasing from 0 to 3 ℃, including sugar cane, tobacco, wheat, soybean and pea. In third category, N2O emission of crop grew with temperature increasing, for example, the emission of rice, vegetables and fruit trees increased by 22.8% when the temperature grew from 0 to 3 ℃. [Conclusion] The research indicated that N2O emission in ecosystem of drv farmland increased little with temoerature risina.

Effects of Characteristics of Fly Ash on the Properties of Geopolymer

The properties of two types of fly ash geopolymers made from class F fly ashes produced in wet bottom and dry bottom boilers were investigated in the present study. The source material used in the geopolymer concrete was activated with sodium hydroxide and sodium silicate solution. The results revealed that the geopolymer produced with wet bottom boiler fly ash(CZ-FA)hardened quickly, and had higher early-age strength and lower shrinkage than the geopolymer produced with dry bottom boiler fly ash(SX-FA). The compressive strength of the two geopolymers made from CZ-FA and SX-FA was 45 MPa and 15 MPa respectively when cured at 60 ℃ and delayed for 14 d. However, after 90 days' delay, the compressive strength of both the samples is almost the same, up to 80 MPa. Nearly 20% volume shrinkage of the samples made from SX-FA was much higher than that made from CZ-FA, which was almost zero. XRD, SEM/EDS and FT-IR were used to analyze the main reason of the differences.

Global Warming Induced Sea Level Rise on Soil, Land and Crop Production Loss in Bangladesh

Available data have been analyzed to assess impacts of global warming induced sea level rise on loss of soil and land resources and their implications on food security of Bangladesh. Scientists believe that because of sea level rise coastal zone of Bangladesh has already experienced noticeable impacts especially in terms of area of inundation and erosion, saline intrusion, loss of soil and land, loss of crop production in addition to migration of people from vulnerable areas. The loss of land mass and degradation of soil and land resources will adversely affect national food production and thereby food security. Sea level rise impacts are really high for Bangladesh, though the country plays insignificant role in green house gas emission. Development and implementation of adaptation policies and taking initiatives to realize those policies are the right ways to respond to sea level rise impacts in Bangladesh.

Carbon-emission calculation of electromechanical energy consumption of different structures during the construction phase

Due to the use of mechanical and electrical equipments in different buildings during construction phase, energy consumption produces large amounts of carbon emissions.Based on the energy use of China, we established a formula that was applicable to carbon-emission calculation, and discussed carbon-emission characteristics of concrete structures and steel construction.Owing to the difference of electrical and mechanical equipment used in construction phase, the results show that under the same conditions, the carbon emission intensity of a concrete structure building is much higher than that of a steel building.At last, we also put forward some emission reduction measures based on the calculation data of different buildings.

Effect of intensity and duration of freezing on soil microbial biomass,extractable C and N pools,and N2O and CO2 emissions from forest soils in cold temperate region

Freezing can increase the emissions of carbon dioxide （CO2） and nitrous oxide （N2O） and the release of labile car- bon （C） and nitrogen （N） pools into the soil. However, there is limited knowledge about how both emissions respond differ- ently to soil freezing and their relationships to soil properties. We evaluated the effect of intensity and duration of freezing on the emissions of CO2 and N2O, net N mineralization, microbial biomass, and extractable C and N pools in soils from a mature broadleaf and Korean pine mixed forest and an adjacent secondary white birch forest in northeastern China. These soils had different contents of microbial biomass and bulk density. Intact soil cores of 0-5 cm and 5-10 cm depth sampled from the two temperate forest floors were subjected to -8, -18, and -80℃ freezing treatments for a short （10 d） and long （145 d） duration, and then respectively incubated at 10~C for 21 d. Soil cores, incubated at 10℃ for 21 d without a pretreatment of freezing, served as control. Emissions of N20 and COz after thaw varied with forest type, soil depth, and freezing treatment. The differ- ence could be induced by the soil water-filled pore space （WFPS） during incubation and availability of substrates for N20 and CO2 production, which are released by freezing. A maximum N2O emission following thawing of frozen soils was observed at approximately 80% WFPS, whereas CO2 emission from soils after thaw significantly increased with increasing WFPS. The soil dissolved organic C just after freezing treatment and CO2 emission increased with increase of freezing duration, which paralleled with a decrease in soil microbial biomass C. The cumulative net N mineralization and net ammonification after freezing treatment as well as N2O emission were significantly affected by freezing temperature. The N2O emission was nega- tively correlated to soil pH and bulk density, but positively correlated to soil KzSO4-extractable NO3 -N content and net am- monification. The CO2 emission was positively correlated to the cumulative net N mineralization and net ammonification. From the above results, it can be reasonably concluded that for a wide range of freezing temperature and freezing duration, N2O and CO2 emissions after thaw were associated mainly with the changes in soil net N mineralization and the availability of substrate liberated by freezing as well as other soil properties that influence porosity.

Substrate availability regulates the suppressive effects of Canada goldenrod invasion on soil respiration

Invasive alien plants not only decrease riparian vegetation diversity but also alter wetland ecosystem carbon processes,especially when they displace the original vegetation.Invasive Canada goldenrod(Solidago canadensis L.)has colonized large areas of disturbed and undisturbed land in southeastern China,yet little is known regarding how it affects soil carbon cycling.To explore the response patterns of soil respiration following S.canadensis invasion and their driving mechanisms,an observational field study and a greenhouse experiment simulating invasion were performed.In the field study,soil respiration was measured weekly from 21th July 2018 to 15th December 2018.In the greenhouse experiment,soil,autotrophic and heterotrophic respiration were measured every 1st and 15th of the month from 15th July 2019 to 15th December 2019.Soil,autotrophic and heterotrophic respiration were measured using a closed-chamber system with the deep gauze collar root exclusion method.Solidago canadensis invasion appeared to decrease the total soil CO_(2) emissions in both the field study and the greenhouse experiment.The suppressive effects on soil respiration may be attributed to S.canadensis invasion-induced alterations in the quality and quantity of available soil substrate,suggesting that S.canadensis invasion may impact soil carbon cycling via plant-released substrates and by competing for the soil available substrate with native plant and/or soil microbes.These results have substantial implications for estimations of the effects of invasive plants on belowground carbon dynamics and their contribution to the warming world.