| 引用本文: | 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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| 摘要: |
| 【目的】探明宁夏中部干旱带压砂田砾石在干湿循环下的劣化情况。【方法】以压砂地常用覆盖砾石—灰绿板岩为研究对象，通过淋水实现干湿循环试验，得到不同劣化程度砾石试样。利用SEM及PCAS计算得到劣化后砾石试样的各种参数并监测各阶段砾石质量损失。【结果】（1）初始阶段大粒级砾石劣化程度总体高于小粒级，干湿循环下孔隙连通性增强，出现大量碎屑与絮状矿物；（2）干湿循环后砾石粒级同孔隙数量成正比，同砾石平均孔隙面积成反比，孔隙的均匀系数较初始大幅升高，最大增幅达129.4%。粒级越大吸水率越小，粒级0.5~2 mm压砂砾石在250、125 mL淋水下较初始增幅最高，分别增加75.05%、56.60%；（3）干湿循环后压砂砾石阶段质量损失率、累积质量损失量与粒级成反比，其中粒级0.5~2 mm压砂砾石在整个循环中受温度影响较敏感，其累积质量损失量在250 mL淋水量下比125 mL提高27.66%。【结论】在施加干湿循环影响下，小粒级压砂砾石劣化速度和程度总体大于大粒级，砾石首先要从大粒级劣化为小粒级，再劣化成壤。研究成果可为宁夏中部干旱带压砂砾石劣化成壤提供理论依据。 |
| 关键词: 干湿循环;扫描电镜;孔隙;吸水率;质量损失率;PCAS |
| DOI： |
| 分类号:S151 |
| 基金项目:国家自然科学基金(51869023, 52169010)；宁夏自然科学基金重点项目(2021AAC02008)；国家重点研发项目（2021YFD1900600）；宁夏高等学校一流学科建设资助项目(NXYLXK2021A03)；宁夏重点研发计划项目(2019BEH03010) |
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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 |
