石灰改良土的土水特征曲线及其冻结特征曲线∗

土水特征曲线反映了非饱和土的持水特性,与土体的水力特性及力学特性密切相关。土的冻结特征曲线表示土体中液态水的势能与含水率之间的关系,也可以用来描述土体的持水特性。以黄土为研究对象,利用低温恒温冷浴结合核磁共振系统(NMR)测得未处理黄土以及石灰改良土的冻结特征曲线,根据冻结温度降低法计算得出试验土样0 ℃时对应的土水特征曲线。另外,采用滤纸法在0 ℃附近得到实测的土水特征曲线,将这两结果进行对比分析,并讨论了抽真空饱和过程对土样的土水特征曲线的影响。通过滤纸法测得的土水特征曲线与非饱和土样的冻结特征曲线具有较好的一致性,两者之间存在差异很小。土样在饱和状态下利用冻结温度降低法得到的孔隙水总势能ψ与质量含水率ω关系曲线位于非饱和土样结果的下方,这可能是因为饱和土样在冻结过程中会发生冻胀现象,土样结构被破坏,孔隙增大,土样持水性能下降。     

基于安全标准化的非煤矿山安全管理系统研究

根据金属非金属露天矿山安全标准化的要求和企业自身安全生产管理需求,分析矿山安全标准化系统要素及其PDCA运行模式,提出创建矿山安全标准化系统的过程思路。基于矿山安全标准化和现代安全管理理念,采用B/S应用模式研发露天矿山"现代安全管理系统",对系统功能和优点进行深入分析,简要阐述系统的应用方式和运行效果。     

Preparation and characterization of modified dual network dust suppression gel based on sodium alginate and soluble starch

Aiming at the problems of complex environment and serious dust pollution in large open-pit coal yards, a dust suppression gel with a dual network structure was prepared by modifying the soluble starch and sodium alginate with iron ions. The changes of functional groups, thermal stability, and morphology structure before and after the reaction were analyzed by FTIR, TG-DSC, and SEM, and the formation mechanism of the dual network was revealed by XPS. Furthermore, the water absorption and water retention experiments proved that the dual network structure is more conducive to water retention than the single-layer network. According to molecular dynamics simulations and contact angle experiments, gel and adsorbed water molecules can approach coal dust molecules on their own to contact, wet, and combine with coal dust. The adhesion test proved that the dust suppression gel with iron ions had better adhesion to dust. The anti-freezing test shows that the dust suppression gel has good anti-freezing performance. The antifreeze test shows that the dust suppression gel still has excellent freeze–thaw resistance at the test temperature of??-20℃. The mechanical property test shows that the dust suppressant gel can prevent the product from being damaged by external force. The acid and alkali resistance experiments showed that the acid and alkali resistance of the gel was improved under the condition of iron ion modification, and the flying of coal powder was effectively prevented. This research provides a new theoretical idea for coal dust control in complex environment.