海底表层的结构物在使用中可能受到动荷载作用,为保证其的长期稳定性,有必要对海床表层的深海超软土动力学特性展开研究。使用Anton Paar MCR302流变仪,采用应变控制模式,对含水率高于液限的深海超软土进行动态剪切测试,研究动态流变参...海底表层的结构物在使用中可能受到动荷载作用,为保证其的长期稳定性,有必要对海床表层的深海超软土动力学特性展开研究。使用Anton Paar MCR302流变仪,采用应变控制模式,对含水率高于液限的深海超软土进行动态剪切测试,研究动态流变参数、动剪切模量G和阻尼比λ的变化规律。结果表明,随着剪切应变的增大,深海超软土的变形由可恢复的弹性变形主导逐渐过渡为不可恢复的黏性变形主导。通过建立动态流变参数与动剪切模量G和阻尼比λ的关系,探讨了深海超软土的动力特性。根据深海超软土动剪切模量G的变化特征,提出了峰值参考应变的概念,建立了最大动剪模量G_(max)与归一化含水率w/w_(p)(w为含水率,w_(p)为塑性含水率)的关系。结果还显示,相较于常规黏土,深海超软土的G/G_(max-γ)(γ为剪切应变)曲线衰减较快,且受塑性指数影响较小。深海超软土的阻尼比整体偏高,并随剪切应变的增大快速上升。根据试验结果,给出描述深海超软土G/G_(max-γ)、λ-γ曲线的数学模型。展开更多
In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The u...In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The undocking clearance of the HYSY 228 is smaller than 1 m;therefore,the barge shows highly nonlinear hydrodynamic characteristics,and it is difficult to be accurately simulated by numerical analysis.Thus,it is necessary to obtain the hydrodynamic characteristics and laws of the float-over barge at different water depths by using tank model test,to provide some reference and guidance for float-over operations in shallow water.展开更多
文摘海底表层的结构物在使用中可能受到动荷载作用,为保证其的长期稳定性,有必要对海床表层的深海超软土动力学特性展开研究。使用Anton Paar MCR302流变仪,采用应变控制模式,对含水率高于液限的深海超软土进行动态剪切测试,研究动态流变参数、动剪切模量G和阻尼比λ的变化规律。结果表明,随着剪切应变的增大,深海超软土的变形由可恢复的弹性变形主导逐渐过渡为不可恢复的黏性变形主导。通过建立动态流变参数与动剪切模量G和阻尼比λ的关系,探讨了深海超软土的动力特性。根据深海超软土动剪切模量G的变化特征,提出了峰值参考应变的概念,建立了最大动剪模量G_(max)与归一化含水率w/w_(p)(w为含水率,w_(p)为塑性含水率)的关系。结果还显示,相较于常规黏土,深海超软土的G/G_(max-γ)(γ为剪切应变)曲线衰减较快,且受塑性指数影响较小。深海超软土的阻尼比整体偏高,并随剪切应变的增大快速上升。根据试验结果,给出描述深海超软土G/G_(max-γ)、λ-γ曲线的数学模型。
文摘In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The undocking clearance of the HYSY 228 is smaller than 1 m;therefore,the barge shows highly nonlinear hydrodynamic characteristics,and it is difficult to be accurately simulated by numerical analysis.Thus,it is necessary to obtain the hydrodynamic characteristics and laws of the float-over barge at different water depths by using tank model test,to provide some reference and guidance for float-over operations in shallow water.
文摘[目的]比较弹性髓内钉(elastic stable intramedullary nail,ESIN)固定儿童长度不稳定与稳定胫骨干骨折的临床效果。[方法]回顾性分析2016年1月—2021年11月收治于本院采用弹性髓内钉治疗的84例胫骨干骨折患儿资料,其中,不稳定骨折32例,稳定骨折52例。比较两组围手术期、随访及影像结果。[结果]两组患儿手术时间、切口总长度、术中失血量、切口愈合等级、住院时间的差异均无统计学意义(P>0.05),不稳定组术中透视次数显著多于稳定组[(12.4±1.5)次vs (10.3±1.7)次,P<0.05]。随访时间平均(13.3±2.3)个月,两组患者恢复术后完全负重时间的差异无统计学意义(P<0.05)。随术后时间推移,两组AOFAS评分、踝背伸-跖屈ROM均显著增加(P<0.05)。相应时间点,两组AOFAS评分和踝背伸-跖屈ROM的差异均无统计学意义(P>0.05),末次随访时,两组Johner-Wruh评级的差异无统计学意义(P>0.05),两组患者步态和下蹲活动均正常。影像方面,与术前相比,术后两组胫骨对位对线、双侧胫骨长度差(leg length discrepancy,LLD)和胫骨成角均显著改善(P<0.05)。术后即刻不稳定组胫骨对位对线[优/良/差,(9/18/5) vs (33/18/1),P<0.05]、双胫骨长度差[(2.1±2.2) mm vs (0.7±1.3) mm,P<0.05]均显著不及稳定组,两组胫骨成角的差异无统计学意义(P>0.05);末次随访时,两组上述指标的差异均无统计学意义(P>0.05)。两组影像骨折愈合时间的差异无统计学意义(P>0.05)。[结论] ESIN是治疗学龄期长度稳定胫骨干骨折患儿安全有效的方法,同样适用于长度不稳定型骨折,虽然术后长度不稳定型骨折短缩的可能性较大,但过度生长会代偿最终的下肢长度差异。
