双环氧防腐配重管三种防滑脱工艺试验研究

部分海底油气输送管道通常采用双层熔结环氧粉末层加混凝土配重层结构。由于上述双层熔结环氧粉末层外表面较为光滑,因此在搬运铺设过程中,混凝土配重层容易出现层间脱落现象。为此采用了聚脲起脊法(A法)、冷缠带缠绕法(B法)及热缩带+冷缠带法(C法)防滑脱工艺制作海管以改善上述性能。试验结果表明:采用A法制作的海管混凝土配重层,其最大的抗剪切强度为0.057MPa;采用B法,其值为0.08MPa;采用C法,其值为0.093MPa。采用A法制作的海管混凝土配重层,由于聚脲材料表层非极性基团定向排布形成光滑的憎水表面,另外聚脲的立体网状结构在混凝土轴向剪切力的作用下可能发生破坏,因而其抗剪切性能较差。采用B法制作的配重层,由于冷缠带表面较为粗糙,同时所使用的高粘性橡胶材料具有较高的粘结力,因而提高了配重层的抗剪切力。采用C法制作的配重层,由于热收缩带被包裹在冷缠带内层,它增加了防滑层的起脊高度,因而进一步提高了配重层的抗剪切强度。但冷缠带高粘接性的防腐胶层会随轴向剪切力作用的增加而发生蠕变,从而导致配重层的最终滑移脱落。

Experimental Research on Three Anti-slip Application Processes for Pipes with Concrete Weight Coating on Two-layer FBE

The external coatings consisting of two-layer fusion bonded epoxy（FBE） and concrete weight coating（CWC）are commonly applied in oil/gas submarine pipelines. However,concrete weight layer slip could easily happen during transportation and pipe laying because the outer surface of two-layer FBE is very smooth. To solve this problem,the pipes external coatings made by three anti-slip application processes respectively called ＂polyurea ridging method＂（method A）,＂cold-applied tape method＂（method B） and ＂cold-applied tape plus heat shrinkable sleeve method＂（method C） have been investigated. The test results show that shearing strengths between the CWC and FBE are 0.057 MPa,0.08 MPa and 0.093 MPa respectively corresponding to method A,method B and method C. In method A, the shearing strength is low because the nonpolar group directional arrangement forms smooth hydrophobic surface and the tridimensional reticulation of polyurea may rupture under CWC axial shearing action;In method B,the shearing strength increases because the cold-applied tape surface is comparatively coarse and the high adhesion rubber has high adhesion;In method C,the shearing strength is high because the heat shrinkable sleeve is enwrapped by cold-applied tape so as to increase the ridging height of anti-slip layer,but it will creeps with the increase of axial searing and lead to CWC slip and break.