地震工程学报
地震工程學報
지진공정학보
China Earthquake Engineering Journal
2015年
1期
61-67,81
,共8页
吸力锚%循环荷载%多孔介质海床%振荡孔压%残余孔压%上拔承载力
吸力錨%循環荷載%多孔介質海床%振盪孔壓%殘餘孔壓%上拔承載力
흡력묘%순배하재%다공개질해상%진탕공압%잔여공압%상발승재력
suction anchor%cyclic loading%porous seabed%oscillatory pore-pressure%residual pore-pressure%uplift capacity
吸力锚基础海上安装方便、定位精确且具有较大上拔承载力，可作为张力腿平台的系泊基础，在深水油气工程应用广泛。服役过程中，作用在吸力锚基础上的荷载一般为一定预张力上的单向循环动力作用，动力荷载可分为波频荷载和二阶低频慢漂荷载，其中波频荷载的幅值较小但周期短，低频荷载幅值较大但周期较长。本文建立多孔介质海床中吸力锚在定常力基础上承受循环上拔荷载的有限元模型，对锚体周围的孔压响应特性进行数值计算与分析，重点分析比较波频荷载和低频慢漂荷载作用下的振荡和残余孔压的变化趋势与影响范围。研究表明，循环上拔荷载作用下吸力锚外侧浅层土体孔压累积显著，降低土体有效应力，弱化筒壁-土体摩擦阻力，有可能引起吸力锚失效模式的转化；循环荷载的幅值和周期都将对孔压响应的大小和分布造成一定影响。
吸力錨基礎海上安裝方便、定位精確且具有較大上拔承載力，可作為張力腿平檯的繫泊基礎，在深水油氣工程應用廣汎。服役過程中，作用在吸力錨基礎上的荷載一般為一定預張力上的單嚮循環動力作用，動力荷載可分為波頻荷載和二階低頻慢漂荷載，其中波頻荷載的幅值較小但週期短，低頻荷載幅值較大但週期較長。本文建立多孔介質海床中吸力錨在定常力基礎上承受循環上拔荷載的有限元模型，對錨體週圍的孔壓響應特性進行數值計算與分析，重點分析比較波頻荷載和低頻慢漂荷載作用下的振盪和殘餘孔壓的變化趨勢與影響範圍。研究錶明，循環上拔荷載作用下吸力錨外側淺層土體孔壓纍積顯著，降低土體有效應力，弱化筒壁-土體摩抆阻力，有可能引起吸力錨失效模式的轉化；循環荷載的幅值和週期都將對孔壓響應的大小和分佈造成一定影響。
흡력묘기출해상안장방편、정위정학차구유교대상발승재력，가작위장력퇴평태적계박기출，재심수유기공정응용엄범。복역과정중，작용재흡력묘기출상적하재일반위일정예장력상적단향순배동력작용，동력하재가분위파빈하재화이계저빈만표하재，기중파빈하재적폭치교소단주기단，저빈하재폭치교대단주기교장。본문건립다공개질해상중흡력묘재정상력기출상승수순배상발하재적유한원모형，대묘체주위적공압향응특성진행수치계산여분석，중점분석비교파빈하재화저빈만표하재작용하적진탕화잔여공압적변화추세여영향범위。연구표명，순배상발하재작용하흡력묘외측천층토체공압루적현저，강저토체유효응력，약화통벽-토체마찰조력，유가능인기흡력묘실효모식적전화；순배하재적폭치화주기도장대공압향응적대소화분포조성일정영향。
Suction anchors are widely used in deep sea oil and gas engineering as a foundation for spars and TLPs because of their considerable uplift capacity and convenient installation.The suc-tion anchor mainly sustains dynamic loads transmitted from the mooring line except for steady loads.The dynamic loads can be divided into two,wave-frequency loads with smaller amplitude and shorter period,and the second-order slow drift loads with larger amplitude and longer period. When the suction anchor is subjected to dynamic uplift loads with different frequencies and ampli-tudes,pore pressures increase in the soil around the anchor.In this study,to investigate the devel-opment of oscillatory pore-pressure and the accumulation mechanism of residual pore pressure in the seabed soil,a finite element model of a suction anchor embedded in a porous seabed subjected to dynamic uplift forces is constructed.On the basis of a steady uplift load,the pressure distribu-tion and development under dynamic loads with different amplitudes and periods are contrasted. The results indicate that oscillatory and residual pore-pressure responses are significant around the anchor.Negative oscillatory pore-pressures mainly appear at the lower part of the anchor.Re-sidual pore-pressure builds-up in the shallow soil,reducing the soil effective stress and the friction between the anchor and soil.Consequently,the failure mechanism may change and the uplift ca-pacity is reduced.
