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891.
武威市位于甘肃省中部,是一座典型的农业城市,分布有大量农业耕地。由于土壤疏松,地面容易受到降水和地下水的影响,易发生地面沉降地质灾害对居民的生产、生活造成不利影响。本文利用2017年2月至2022年12月的Sentinel-1A数据,通过PS-InSAR技术提取了武威市的地面沉降监测数据,包括视线向形变速率和累积形变量。对形变场的时空分布特征进行了详细分析,并引入Mogi模型反演地下深部变形范围。最后,结合研究区的降水数据和GRACE重力卫星获取到由陆地水负荷引起的地表形变数据,并对研究区的沉降成因进行了初步分析。结果表明,研究区存在两个主要沉降区,其中主沉降区A的最大累积沉降量达到-290.9 mm,视线向形变速率为-52.0 mm/a;主沉降区B的沉降量达到-178.1 mm,视线向形变速率为-43.8 mm/a。地表沉降呈现周期性变化,且向东南方向逐步扩展,与降水和地下水变化特征相似。通过Mogi模型反演,得出了主沉降区的地下影响范围(半径)和深度,其中主沉降区A为40.96 m和133.67 m,主沉降区B为38.60 m和140.78 m。按季节划分统计形变数据,结果表明,由于研究区所属干旱区,自然降水无法对地面沉降产生显著影响,而农耕时大量地下水的抽取才是导致区域地面沉降的主要原因。
相似文献892.
893.
894.
In this work, the elastic buckling of porous solids was investigated using a lattice spring model (LSM). The capability of the LSM to solve elastic buckling problems was comprehensively verified by comparing well-established numerical and analytical solutions. Following this, the buckling of a porous solid was studied, in which two porous structures were considered, ie, the random porous model and the Voronoi porous model. The results reveal that both the porosity and the shape of the pores influence the elastic buckling bearing capacity of the porous solid. Finally, the mechanical responses of a porous solid with an extra high porosity (0.85) were numerically investigated. Our numerical results demonstrated that the nonlinear elastic response of the porous solid might come from its mesoscale elastic buckling. This work shows the ability and promise of using the LSM as a fundamental numerical tool for the deep investigation of the buckling mechanical behavior of porous solids. 相似文献
895.
阐述了大汶河流域洪涝灾害的特点,并对洪涝灾害发生的原因进行了分析,提出了预防为主、综合治理、系统防治和重点防治相结合、标本兼治的防治思路及具体防治对策. 相似文献
896.
Investigating soil thermodynamic parameters of the active layer on the northern Qinghai-Tibetan Plateau 总被引:2,自引:1,他引:2
Ren Li Lin Zhao Tonghua Wu Yongjian Ding Yao Xiao Yongliang Jiao Yanhui Qin Yufei Xin Erji Du Guangyue Liu 《Environmental Earth Sciences》2014,71(2):709-722
The soil thermodynamic parameters, including thermal conductivity, diffusivity and volumetric capacity within the active layer on the northern Tibetan Plateau, were calculated using the measured data of soil temperature gradient, heat flux, and moisture at four stations from October 2003 to September 2004. The results showed that the soil thermodynamic parameters exhibited clear seasonal fluctuation. The thermal conductivity and diffusivity in summer and autumn at Beiluhe, Kexinling, and Tongtianhe were larger than those in winter. The volumetric thermal capacity causes an opposite change; it was larger in autumn and winter than in summer. In spring, the soil thermal conductivity at the Kekexili station was larger than that in summer. Generally, fine-grained soils and lower saturation degrees in the topsoil might be a reason for the lower soil thermal conductivity in winter. For a given soil, soil moisture was the main factor influencing the thermodynamic parameters. The unfrozen water content that existed in frozen soils greatly affected the soil thermal conductivity, whose contribution rate was estimated to be 55 %. The thermodynamic parameters of frozen soils could be expressed as a function of soil temperature, volumetric ice content and soil salinity, while for the unfrozen ground the soil moisture content is the dominant factor for those thermal parameters. As for the soil thermal diffusivity, there exists a critical value of soil moisture content. When the soil moisture content becomes less than a critical value, the soil thermal diffusivity increases as the soil moisture content rises. 相似文献
897.
强度和变形参数的变化对土工有限元计算的影响 总被引:4,自引:2,他引:4
在土工问题的数值分析中,包含变形模量E、泊松比 两个变形参数的增量线弹性模型是一种常用的计算模型,研究和掌握E和 两个参数对土工有限元计算的影响有助于分析计算成果。首先,设想固定某一个参数而观察另一个参数变化对计算结果的影响;然后,说明用强度折减有限元法分析土坡稳定安全系数时,实际上已同时考虑了变形参数的影响。可采用剪应力? xy的等值线近似形成滑动面,滑动面单元的应力水平S等于1和特征点的位移发生突变共同作为失稳判据;最后,是用强度参数为纽带探讨这两个变形参数的互相变化关系,即E愈大,则土的强度愈大,? 愈小。 相似文献
898.
The granite collected from the Yinshan Mountain and kaolinite has been selected for the leaching and adsorption experiment,respectively,aiming to clarify the enrichment processes of Li and Ga during the deposition.Results suggest both Li and Ga could be leached out from granite by using different acid solutions of different p H and kaolinite can adsorb Li and Ga with varying degrees.Lithium and Ga had the highest leaching ratio when p H=1.Special geological events(e.g.volcanic eruptions and wildfires),which could result in very low p H values of water in peatland,may have accelerated the release of Li and Ga from the source rocks.Kaolinite has the highest adsorption fraction was obtained at p H=8.The different characteristics of Li and Ga displayed in the leaching and adsorption experiments probably result from the different occurrences and enrichment processes of Li and Ga in the coals.Lithium was probably enriched before the Li carriers(e.g.kaolinite)had been transported into paleomires because of its high leaching ratio and high adsorption fraction under neutral and alkaline conditions,whereas Ga was more likely concentrated by kaolinite and other carriers after it had been transported into the peat mires. 相似文献
899.
本文探讨了灞河流域岩溶特征、CO2估算方法和CO2吸收量。观测资料表明,灞河流 域河水中pH值在冬春季高,夏秋季低,而HCO3含量通常与pH相反。河水和黄土地下水中 pH值、HCO3等化学成分含量与北方南部石灰岩区岩溶水基本相同,表明该区现代岩溶作用 明显,黄土地层也在不断吸收CO2,并对全球碳循环有重要影响。雨水富含CO2,其中约有 82%的CO2被岩溶过程吸收,18%左右的随河水流失。根据一个流域CO2输入量和输出量,可 以计算岩溶过程中 CO2吸收量。计算表明,灞河流域现代岩溶过程中每年吸收的 CO2约为5632.8t。 相似文献
900.