Simulation analysis for O-cell test of pile and the interaction of upper pile and lower pile

In this paper,the soil-pile system of O-cell test of pile is simplified as an axi-symmetric problem.By using aggregation of quadrilateral isoparametric elements to simulate pile and soil,setting Goodman’s elements between pile and soils,a method of numerical simulation analysis on O-cell test of pile is presented with the consideration of nonlinear mechanical behavior of soils and pile-soil interface.The method is applied to the analysis of a case of O-cell test of pile.The load-displacement curves and axial force curves of upper pile and lower pile obtained from the O-cell test of pile are fitted,and parameters of the mechanical model of soils and interface are determined.Analysis results validate that the numerical simulation analysis method put forward in this paper is applicable.Furthermore,the interaction and influence of upper pile and lower pile in the O-cell test are also studied with the method.The result shows that if load box is located in a soil layer with fine mechanical behavior,the interaction of upper pile and lower pile in O-cell test can be ignored generally.     

金属氢化还原法合成硼氢化钠

硼氢化钠是一种用途很广的络合金属氢化物还原剂。本文介绍了利用硼砂、金属钠和氢气为原料，在常压下合成硼氢化钠的新方法。用异丙胺萃取，得白色晶体硼氢化钠。     

基于低影响开发的雨水花园设计研究

随着城市化进程的加速,各种城市问题逐渐凸显。其中水污染、水资源匮乏及城市内涝近年来逐渐受到关注。在此背景下,低影响开发理念成为风景园林行业热点。本文探讨了基于低影响开发的雨水花园对城市建设的重要价值,并系统地阐述雨水花园设计方法,重点分析雨水花园植物的选择与配植方法。并以上海SOHO虹口中心庭院景观设计为例,分析和研究了基于低影响开发的雨水花园设计实践方法。