Because ice-high foundation soil is widely distributed in permafrost regions,the correct preparation of ice-high specimens is of critical interest in engineering design for foundation stability.Past research has shown that the uniaxial compression strength of ice-high frozen soils changes as the ice or total water content increases; the differences of different methods of specimen preparation are analyzed here and the advantages and disadvantages of them are presented.It is confirmed that the role of crushed ice is significantly different from that of naturally frozen ice in frozen soils,and the size and amount of crushed ice will influence the strength and deformation mechanism of frozen soils.Therefore,it is strongly recommended that when a ice-high specimen is artificially prepared,the ice should be frozen through natural means and not be replaced with crushed ice.
工程中大量的实体对象基本都是以AutoCAD图纸的形式表现出来,露天矿开采也不例外,AutoCAD电子版图纸可以灵活、详细地表现和编辑工程实体对象的各项内容,在生产过程中有着无可替代的作用。但AutoCAD的缺点也是明显的:不能对图形中大量数据信息进行处理。如何利用AutoCAD天然的优势在AutoCAD平台上实现生产管理功能,就是要借助Auto CAD链接外部数据库和其他应用程序,利用它们的数据存储、数据查询、数据处理及数据交换的能力,弥补AutoCAD的缺点,使图形具备智能化。利用AutoCAD平台下的数据库链接功能Dbconnect,通过Active X Data Object(ADO)外部数据通信技术和Connectivity Automation Objects(CAO)对象数据库链接技术,结合服务器型数据库SQL的多条件查询、存储数据功能和EXCEL的快捷方便的数据处理能力,编制AutoCAD VBA二次开发程序,实现了某露天矿生产工艺的信息化管理。
To investigate the mechanical properties of ice-saturated frozen soil, a series of triaxial tests under various confining pressures(0.5 to 9.0 MPa) on ice-saturated frozen loess with ice content of 23.7% were carried out at a temperature-6 °C, and at 1.25 mm/min of loading rate. The triaxial tests include two loading modes, one with monotonic loading(i.e., triaxial compression), and another with static cycle loading. The test results under triaxial compression show that the strength and deformation behaviors of ice-saturated frozen loess are affected by confining pressure. According to the test results of triaxial loading-unloading cycle test, the elastic modulus evolution with the number of cycles under different confining pressures are analyzed.
