Partial drainage often occurs during piezocone penetration testing on Yellow River Delta silt because of its intermediate physical and mechanical properties between those of sand and clay.Yet,there is no accurate unde...Partial drainage often occurs during piezocone penetration testing on Yellow River Delta silt because of its intermediate physical and mechanical properties between those of sand and clay.Yet,there is no accurate understanding for the range of penetra-tion rates to trigger the partial drainage of silt soils.In order to fully investigate cone penetration rate effects under partial drainage condi-tions,indoor 1 g penetration model tests and numerical simulations of cavity expansion at variable penetration rates were carried out on the Yellow River Delta silt.The boundary effect of the model tests and the variation of key parameters at the different cavity ex-pansion rates were analyzed.The 1 g penetration model test results and numerical simulations results consistently indicated that the penetration rate to trigger the partially drainage of typical silt varied at least three orders of magnitude.The numerical simulations also provide the reference values for the penetration resistance corresponding to zero dilation and zero viscosity at any given normalized penetration rate for silt in Yellow River Delta.These geotechnical properties can be used for the design of offshore platforms in Yel-low River Delta,and the understanding of cone penetration rate effects under the partially drained conditions would provide some technical support for geohazard evaluation of offshore platforms.展开更多
文摘目的比较超声引导下腹横筋膜平面(TFP)阻滞与腹横肌平面(TAP)阻滞在剖宫产术后镇痛中的效果。方法择期蛛网膜下腔阻滞下行剖宫产术产妇60例,年龄20~35岁,体重50~75 kg,ASAⅠ或Ⅱ级,采用随机数字表法分为两组:腹横筋膜平面阻滞组(TFP组)和腹横肌平面阻滞组(TAP组),每组29例。术毕TFP组行超声引导下双侧腹横筋膜平面阻滞,TAP组行超声引导下双侧腹横肌平面阻滞,两组均每侧注射0.375%罗哌卡因1.25 mg/kg。术后均行曲马多PCIA,若VAS疼痛评分≥4分,肌肉注射曲马多100 mg行补救镇痛。记录术后6、12、24、36、48 h PCIA中曲马多累积用量;记录术后48 h内曲马多补救镇痛情况;记录镇痛期间恶心呕吐、局麻药中毒、呼吸抑制、穿刺部位血肿、穿刺部位感染、腹膜刺穿造成腹腔内注射等不良反应的发生情况。结果与TAP组比较,TFP组术后6、12、24、36、48 h PCIA中曲马多累积用量明显减少(P<0.05),术后48 h内曲马多补救镇痛率明显降低(P<0.05)。两组镇痛期间恶心呕吐发生率差异统计学意义。两组均无其他不良反应发生。结论与超声引导下腹横肌平面阻滞比较,腹横筋膜平面阻滞可减少剖宫产术后阿片类药物用量,镇痛效果更佳。
基金supported by the National Natural Science Foundation of China(Nos.U1806230,U2006213),and the Fundamental Research Funds for the Central Univer-sities(No.201962011).
文摘Partial drainage often occurs during piezocone penetration testing on Yellow River Delta silt because of its intermediate physical and mechanical properties between those of sand and clay.Yet,there is no accurate understanding for the range of penetra-tion rates to trigger the partial drainage of silt soils.In order to fully investigate cone penetration rate effects under partial drainage condi-tions,indoor 1 g penetration model tests and numerical simulations of cavity expansion at variable penetration rates were carried out on the Yellow River Delta silt.The boundary effect of the model tests and the variation of key parameters at the different cavity ex-pansion rates were analyzed.The 1 g penetration model test results and numerical simulations results consistently indicated that the penetration rate to trigger the partially drainage of typical silt varied at least three orders of magnitude.The numerical simulations also provide the reference values for the penetration resistance corresponding to zero dilation and zero viscosity at any given normalized penetration rate for silt in Yellow River Delta.These geotechnical properties can be used for the design of offshore platforms in Yel-low River Delta,and the understanding of cone penetration rate effects under the partially drained conditions would provide some technical support for geohazard evaluation of offshore platforms.
