渤海海冰对直桩柱的作用力

EFFECT OF BOHAI ICE CRUSHING STRENGTH ON VERTICAL STRUCTURES

于1990年1月在锦州湾采样,主要测试了在不同的冰温和不同的应变速率下渤海海冰的挤压强度,并且研究了海冰挤压强度与冰温及应变速率的关系。对半径R=2,3,4,5cm圆柱压头的海冰挤压强度R_(CM)进行了试验,由此求得了海冰的局部挤压系数和接触系数。分析了冰块宽度B与桩柱宽度b之比与挤压系数的关系。在—10℃冰温下,对半圆形,压头端部尖角20等于180°,120°,90°,60°五种压头进行了试验,从而求得桩柱的形状系数,建立起大冰原对桩柱挤压作用的最大冰压力公式。

Jacket platforms with vertical or nearly vertical legs are typical structures in the Bohai Sea. Vertical structures may be destroyed by ice crushing against them. This research is aimed at studying the relation between sea ice crushing strength and ice temperature and strain rate. For columnar sea ice at the strain rate that causes the maximum crushing strength the indentation factor is 3.0. The obtained crushing strength of a cylinder indentor (R = 2, 3, 4, 5cm) was used to compute the indentation factor and contact factor of sea ice. The relation between the indentation factor and the ratio of the ice thickness to indentor width is analysed. The indentation factor is not constant but rather is a function of ice thickness to indentor width ratio. For continuous crushing in which the ice is not frozen to indenter, the contact factor is a function of the strain rate. The crushing strength of sea ice was experimented for 5 indentors (semicircle, 2α=180°, 120°, 90°, 60°) at ice temperature -10℃. From this, the shape factor of the pile was obtained. The shape factor is 0.91 for a circular indenter. The value of maximum compressive force of sea ice on a pile in large ice-fields is applicable to ocean engineering.