| Cite this article: | 安文举,李王成,赵广兴,等.干湿循环对宁夏压砂砾石劣化的田间试验研究[J].灌溉排水学报,0,():-. |
| Anwenju,Liwangcheng,Zhaoguangxin,et al.干湿循环对宁夏压砂砾石劣化的田间试验研究[J].灌溉排水学报,0,():-. |
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| Field Test Study on Deterioration of Pressed Sand and Gravel by Dry~wet Cycle in Ningxia |
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Anwenju1, Liwangcheng2, Zhaoguangxin2, Jiazhenjiang2, Liuqiaoling2, Wangjie2, Mumin2, Liyangyang2
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1.Ningxia University;2.School of Civil and Hydraulic Engineering, Ningxia University
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| Abstract: |
| 【Objective】In order to find out the deterioration of gravel in the pressure sand field in the arid belt of central Ningxia under the dry-wet cycle.【Method】We took the lime-green slate, which is commonly covered with gravel in the pressed sand, as the research object, and achieved the dry-wet cycle test by spraying water, and obtained gravel samples with different degrees of deterioration. Various parameters of the degraded gravel samples were calculated by SEM and PCAS, and the quality loss of gravel at each stage was monitored.【Result】(1)In the initial stage, the degradation degree of large-grain gravels is generally higher than that of small~grain gravels, and the pore connectivity is enhanced under the dry-wet cycle, and a large number of debris and flocculent minerals appear; (2)After the dry-wet cycle, the gravel size is proportional to the number of pores, and inversely proportional to the average pore area of the gravel. The uniformity coefficient of pores increases significantly from the initial stage, with a maximum increase of 129.4%. The larger the particle size, the smaller the water absorption rate. The crushed sand and gravel with a particle size of 0.5~2mm has the highest increase compared with the initial water under 250 and 125 mL water, increasing by 75.05% and 56.60% respectively; (3) After the dry-wet cycle, the mass loss rate and cumulative mass loss in the pressing sand and gravel stage are inversely proportional to the grain size. Among them, the pressed sand and gravel with a grain size of 0.5-2 mm is more sensitive to the influence of temperature in the whole cycle, and its cumulative mass loss is The amount of water sprayed at 250 mL was 27.66% higher than that of 125 mL.【Conclusion】Under the dry-wet cycle, the degradation rate and degree of the small-sized compacted sand gravel are generally greater than that of the large-sized gravel. The gravel first degrades from the large-sized grade to the small-sized grade, and then degrades into soil. The research results can provide a theoretical basis for the degraded soil formation of compacted sand and gravel in the arid zone of central Ningxia. |
| Key words: Dry-wet cycle; SEM; Porosity; Water absorption; Mass loss rate; PCAS |
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