渤海海冰的抗压强度试验研究

在1983—1984年和1984—1985年两个冬季进行的系统现场试验表明:(1)柱状晶体海冰各向导性显著,垂直方向的抗压强度可用水平方向的抗压强度来估算。(2)通常意义下的海冰试样尺寸效应规律不明显。(3)在出现最大抗压强度的应变率范围内,抗压强度可以用冰中所含盐水体积来表达,得到的经验公式可用于渤海的工程结构设计中。     

黄海北部庄河附近海域海冰物理力学特性

研究了黄海北部海冰物理力学性质，试验内容有海冰的晶体结构，单轴压缩强度和弯曲强度，分析了海冰的压缩强度和弯曲强度与冰温，应力率和加载方向的关系。     

北极楚科奇海海冰特征研究——以1999年夏季为例

对北冰洋楚科奇海海冰分布、厚度、气/冰/海界面温度场观测,钻取海冰冰芯,观测冰结构的变化,发现3种海冰组合结构: 1)表面融化型; 2)表面和底部融化型; 3)整体融化型. 海冰结构形成的热力学过程为:在气/冰界面上,海冰上表面吸收辐射能使冰体升温,出现表面融化; 在冰/海水界面上,海冰盘与开阔水域的相间分布、相对运动,将周围温度较高的水体输送到海冰的底部,加热、融化海冰底部; 冰体升温,冰晶间盐水膜首先融化,分离冰晶,破坏海冰整体结构. 冰的相变吸热,使其温度维持在融点, 这些过程均衡了夏季北冰洋的温度变化.     

Summer sea ice characteristics of the Chukchi Sea

During August 1999, we investigated sea ice characteristics; its distribution, surface feature, thickness, ice floe movement, and the temperature field around inter-borders of air/ice/seawater in the Chukchi Sea. Thirteen ice cores were drilled at 11 floe stations in the area of 72°24′ 77°18′N, 153°34′ 163°28′W and the ice core structure was observed. From field observation, three melting processes of ice were observed; surface layer melting, surface and bottom layers melting, and all of ice melting. The observation of temperature fields around sea ice floes showed that the bottom melting under the ice floes were important process. As ice floes and open water areas were alternately distributed in summer Arctic Ocean; the water under ice was colder than the open water by 0.4 2.8℃. The sun radiation heated seawater in open sea areas so that the warmer water went to the bottom when the ice floes move to those areas. This causes ice melting to start at the bottom of the ice floes. This process can balance effectively the temperature fluctuating in the sea in summer. From the crystalline structure of sea ice observed from the cores, it was concluded that the ice was composed of ice crystals and brine-ice films. During the sea ice melting, the brine-ice films between ice crystals melted firstly; then the ice crystals were encircled by brine films; the sea ice became the mixture of ice and liquid brine. At the end of melting, the ice crystals would be separated each other, the bond between ice crystals weakens and this leads to the collapse of the ice sheet.     

渤海北部平整冰抗压强度设计标准研究

分析了1983～1986年在渤海北部鲅鱼圈港做的系列抗压强度试验结果,推荐了较好的抗压强度计算公式。从工程设计角度分析了最低气温对冰温的影响。利用渤海北部历年的冰厚和气象资料,按传热量理论推算出Ⅰ、Ⅱ设计海区历年的极值等效冰温;结合实测的冰盖盐度及其分布,计算出相应的极值等效抗压强度系列。推荐了渤海北部Ⅰ、Ⅱ海区平整冰的抗压强度、温度和盐度的设计值。     

黄河口海区海冰设计强度计算

根据黄河口海区低盐度海冰和黄河冰的冰强度经验公式、冰盖传热量计算公式,分析了几种设计冰厚与设计气温对冰强度的影响。给出了设计气温取-15℃时冰强度与设计冰厚关系的经验公式,给出了设计冰厚分别取0.4m和0.7m时冰强度与设计气温关系的经验公式。计算出的冰强度若干结果及建议值可供胜利油田滨海结构物设计参考使用。     

海冰平面应变断裂韧度 KIC

试验测得海冰平面应变断裂韧度(K_(IC))范围为11—77 kN/m~(3/2),平均值为32kN/m~(3/2)。由试验结果得知海冰的断裂韧度与加载速度、冰晶颗粒、试验温度有密切的关系。这些因素对应力强度因子K_(IC)临界值有较大影响。结果表明,当加载速度增大时,K_(IC)值减小;当温度升高时,K_(IC)值减小。     

-渤海海冰侧限抗压强的试验研究

本文介绍渤海海冰侧限抗压强度试验的部分结果及其在塑性理论中的应用,结果表明,有侧限抗压强度与无侧限抗压强度均随应变率的增大出现延性、过渡和脆性三个破坏阶段,但在有侧限情况下,后两个阶段推迟出现.此外,在侧限应力与侧限应力率、侧向压力系数(等于泊松比)与应变率之间也同样存在上述三个阶段结果还表明,屈服时间随应变率的增大而减小.     

辽东湾海冰单轴压缩长期强度的初步分析

冰的蠕变特性是其自身独特的一种性质,正是由于这一特性才导致了其本构关系的复杂性。室内确定海冰静压力强度特征的标准方法有:恒变形速率或加载速率下的压缩强度试验和恒荷载下的压缩蠕变试验。本文是根据近年来进行的海冰圆柱状试样单轴压缩强度和单轴压缩蠕变试验的结果,分析海冰的长期强度特征并给出统计结果。分析结果还表明海冰的弹性范围很小,即便是单轴压缩强度试验,也只有在加载时间很短的情况下,才表现出拟弹性阶段。