Dynamic Response of Ocean Trestle to Horizontal Impact of Moving Mass

Based on the Winkler hypothesis, a model for analysis of the flexural response of an ocean trestle embedded in layered soil to horizontal impact of a moving mass is developed. By use of the transfer matrix in time domain, one can calculate the flexural dynamic response of a single pile. Then, by use of the boundary conditions of piles at the pile top, the dynamic response of the structure is analyzed. By use of the model proposed in this paper, the interactive force between the moving mass and the structure can be computed based on Work' s kinetic energy theorem and Newton iterative method. Thus the approach does not have to assume the interactive force, while the traditional method have to. The approach more accords with the engineering practice than the traditional method and it is convenient for engineering design.     

软黏土中桶形基础竖向循环加载超重力离心模型试验研究

桶形基础越来越广泛应用于海洋油气平台、海上风机、输电塔、防波堤等构筑物,研究其循环承载特性对以上构筑物服役安全性具有重要意义。通过在软黏土中开展单桶循环上拔以及小间距群桶循环上拔和循环下压超重力离心模型试验,发现循环上拔地基破坏模式为整体破坏,裂隙均呈现圆弧形,循环下压呈现渐进式整体破坏模式,下压过程的挤压作用可明显减小桶周泥面高度,导致其承载力降低。模拟双向受荷工况的循环上拔试验在5次加载后荷载弱化系数开始趋于稳定,远早于单向受荷工况;单向和双向受荷工况循环上拔荷载弱化系数残余稳定值分别为0.31和0.32,循环下压荷载弱化系数最小值为0.35,表明不同加载方式竖向循环荷载作用下,此三者大小均可用软黏土地基灵敏度倒数预估。     

黄旗海湿地——濒临消失的候鸟天堂

正湿地是地球上生物多样性丰富、生产力很高的系统,与森林、海洋并称为全球三大生态系统。1971年全球性政府间《湿地公约》定义的"湿地"是:不论天然或人工、长久或暂时的沼泽地、湿原、泥炭地或水域地带,带有静止或流动、咸水或淡水、半咸水或咸水水体,包括低潮时水深不超过6米的水域。因此,湿地不仅是我们传统认识上的沼泽、泥滩地、滩涂等,还包括河流、湖泊、水库、稻田以及退潮时水深     

砾石土渗透系数确定方法及其在管涌试验中应用

渗透系数作为水文地质学中的重要参数，在基坑建设、矿井涌水问题治理、环境治理等有广泛的应用。通过Kozeny-Carman公式、Kovacs公式、Amer-Award等理论公式计算获得砾石土渗透系数用于计算流速或流量，与管涌试验的实际流速、流量对比和拟合，从而验证参数的有效性和适用性。表明三个理论公式计算与实际数据拟合良好。