考虑颗粒破碎影响的吸力贯入式平板锚安装过程研究
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摘要
吸力贯入式平板锚是一种适用于深海结构的锚泊基础,基于离散单元法对吸力贯入式平板锚在颗粒可破碎地基中的安装过程进行了模拟,探究土颗粒破碎对锚体运动特征、埋深减少等的影响。研究结果表明,土颗粒破碎导致锚板安装受荷旋转过程中发生斜向上的贯穿运动,影响锚的埋深减少。贯穿运动的产生与吸力贯入式平板锚的几何尺寸偏心比大小有关,偏心比很小时,不发生贯穿运动,随偏心比的增大,贯穿运动的程度先提高后下降;与未考虑土颗粒破碎情况比较,土颗粒破碎导致锚体在安装过程中产生的埋深减少远大于在土颗粒不破碎时的埋深减少。同时在土颗粒可破碎地基中,受贯穿运动的影响,吸力贯入式平板锚偏心比达到0.3后,埋深减少不再随锚链拉力倾角增大而线性增加,锚链拉力倾角超过45°后,埋深减少随着锚链拉力倾角增大而增加的速度变快。
The suction embedded plate anchor is a kind of anchor foundation applicable to deep-sea structures. Based on the discrete element method, the installation process of the suction embedded plate anchor in particle breakable foundation is simulated, and the influences of soil particle breakage on motion characteristics of anchor body and loss of embedment are investigated. The results show that the soil particle breakage results in the inclined upward penetrating motion of the anchor plate during the load-rotating process, which affects the embedment loss of the anchor. The penetration motion is related to the eccentricity ratio of geometrical dimensions of suction embedded plate anchor. When the eccentricity ratio is very small, the penetrating motion does not occur. With the increase of eccentricity ratio, the degree of penetration motion first increases and then decreases. Compared with the situation without considering the soil particle breakage, the embedment loss caused by soil particle breakage during the installation of anchor body is much more than that caused by unbroken soil particle. At the same time in particle breakable foundation, under the influences of penetrating motion, when the eccentricity ratio of suction embedded plate anchor reaches 0.3, the loss of embedment no longer increases linearly with the increase of inclination angle of the anchor chain tension. When the inclination angle of the anchor chain tension exceeds 45°, as the inclination angle of the anchor chain tension increases, the loss of embedment is at higher speed.
The suction embedded plate anchor is a kind of anchor foundation applicable to deep-sea structures. Based on the discrete element method, the installation process of the suction embedded plate anchor in particle breakable foundation is simulated, and the influences of soil particle breakage on motion characteristics of anchor body and loss of embedment are investigated. The results show that the soil particle breakage results in the inclined upward penetrating motion of the anchor plate during the load-rotating process, which affects the embedment loss of the anchor. The penetration motion is related to the eccentricity ratio of geometrical dimensions of suction embedded plate anchor. When the eccentricity ratio is very small, the penetrating motion does not occur. With the increase of eccentricity ratio, the degree of penetration motion first increases and then decreases. Compared with the situation without considering the soil particle breakage, the embedment loss caused by soil particle breakage during the installation of anchor body is much more than that caused by unbroken soil particle. At the same time in particle breakable foundation, under the influences of penetrating motion, when the eccentricity ratio of suction embedded plate anchor reaches 0.3, the loss of embedment no longer increases linearly with the increase of inclination angle of the anchor chain tension. When the inclination angle of the anchor chain tension exceeds 45°, as the inclination angle of the anchor chain tension increases, the loss of embedment is at higher speed.
引文
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[7]王腾,严梦.吸力式贯入板锚转动上拔过程的数值模拟研究[J].岩土工程学报,2016,38(1):118-123.(WANGTeng,YAN Meng.Numerical study on keying of suction embedded plate anchors[J].Chinese Journal of Geotechnical Engineering,2016,38(1):118-123.(in Chinese))
[8]CHENG Y P,NAKATA Y,BOLTON M D.Discrete element simulation of crushable soil[J].Géotechnique,2003,53(7):633-641.
[9]张家铭,邵晓泉,王霄龙,等.沉桩过程中钙质砂颗粒破碎特性模拟研究[J].岩土力学,2015,36(1):272-278.(ZHANG Jia-ming,SHAO Xiao-quan,WANG Xiao-long,et al.Discrete element simulation of crushing behavior of calcareous sands during pile jacking[J].Rock and Soil Mechanics,2015,36(1):272-278.(in Chinese))
[2]曹可达,谭慧明,王娇娇,等.吸力贯入式平板锚旋转特性的离散元数值模[J].中国科技论文,2015,10(7):829-833.(CAO Ke-da,TAN Hui-ming,WANG Jiao-jiao,et al.DEMnumerical simulation on keying characteristics of suction embedded plate anchors[J].China Sciencepaper,2015,10(7):829-833.(in Chinese))
[3]GAUDIN C,THAM K H,OUAHSINE S.Plate anchor failure mechanism during keying process[C]//Proceedings of the18th International Offshore and Polar Engineering Conference.2008:613-620.
[4]SONG Z H,HU Y X,O'LOUGHLIN C D,et al.Loss in anchor embedment during plate anchor keying in clay[J].Journal of Geotechnical and Geoenvironmental Engineering,2009,135(10):1475-1485.
[5]WANG D,HU Y X,RANDOLPH M F.Keying of rectangular plate anchors in normally consolidated clays[J].Journal of Geotechnical and Geoenvironmental Engineering,2011,137(12):1244-1253.
[6]WEI Q C,CASSIDY M J,TIAN Y H,et al.Incorporating shank resistance into prediction of the keying behavior of suction embedded plate anchors[J].Journal of Geotechnical and Geoenvironmental Engineering,2015,141(1):334-342.
[7]王腾,严梦.吸力式贯入板锚转动上拔过程的数值模拟研究[J].岩土工程学报,2016,38(1):118-123.(WANGTeng,YAN Meng.Numerical study on keying of suction embedded plate anchors[J].Chinese Journal of Geotechnical Engineering,2016,38(1):118-123.(in Chinese))
[8]CHENG Y P,NAKATA Y,BOLTON M D.Discrete element simulation of crushable soil[J].Géotechnique,2003,53(7):633-641.
[9]张家铭,邵晓泉,王霄龙,等.沉桩过程中钙质砂颗粒破碎特性模拟研究[J].岩土力学,2015,36(1):272-278.(ZHANG Jia-ming,SHAO Xiao-quan,WANG Xiao-long,et al.Discrete element simulation of crushing behavior of calcareous sands during pile jacking[J].Rock and Soil Mechanics,2015,36(1):272-278.(in Chinese))