应用可变T2截止值确定束缚水饱和度   总被引：1，自引：0，他引：1  

苏俊磊  王艳  孙建孟 《吉林大学学报(地球科学版)》2010,40(6):1491-1495,1520

为了得到准确的束缚水饱和度数据,以T2截止值模型为基础,分别用基于经验固定T2截止值、经验可变T2截止值及渗透率Coates模型的可变T2截止值3种方法确定束缚水饱和度,利用常规岩心分析实验数据验证其计算精度.结果表明,基于渗透率Coates模型的可变T2截止值计算核磁束缚水饱和度精度最高,与常规岩心分析束缚水饱和度平均相对误差为9.5%,而且此方法可确定Coates模型中的地区经验系数C、m、n,提高了核磁渗透率的计算精度.  相似文献   

青藏高原羌塘中部双湖早古生代斜长角闪岩年代学及地质意义   总被引：1，自引：0，他引：1  

杨桂花  彭智敏  张璋  关俊雷 《沉积与特提斯地质》2017,37(3):96-102

羌塘盆地中部双湖县齐陇乌如沟出露一套斜长角闪岩,通过对该斜长角闪岩锆石SHRIMP U-Pb定年,获得206Pb/238U加权平均年龄为450.1±5.0Ma,表明该变基性岩形成于晚奥陶世。元素地球化学测试分析表明,SiO_2含量在45.67%~51.68%,Na_2O为0.98%~2.54%,总体呈现明显的高Na、低K的特点。轻、重稀土元素分馏较小,Eu具有轻度的正异常。微量元素Rb、Ba和U元素相对较为富集,Nb、Ta和Zr具有不同程度的亏损。地球化学特征显示具有E-MORB的性质,代表了古特提斯洋壳的残余。齐陇乌如沟斜长角闪岩的年龄与昌宁-孟连结合带的铜厂街蛇绿岩和湾河蛇绿岩形成年龄基本一致,地球化学性质相似,说明龙木错-双湖结合带与昌宁-孟连结合带代表了一个统一的原(古)特提斯洋。  相似文献   

基于三维数值分析的基坑突涌临界水头确定方法     

高广运  柴俊磊  张先林  金清山 《岩土力学》2012,33(Z1):251-256

针对既有基坑突涌稳定分析方法存在的问题,采用应变相关修正剑桥模型（SDMCC）,借助FLAC3D软件建立了考虑承压水作用的三维有限差分模型,得到了坑底隆起变形与承压水头Hw之间的关系。随着承压水头的增大,坑底隆起变形分为3个阶段：缓慢匀速变形、加速变形和急剧匀速变形。提出一种确定基坑突涌临界水头Hwcr的数值方法,并将该方法与其他文献临界水头计算结果进行对比。  相似文献   

Flow-Induced Vibration of Four Cantilever Cylinders Arranged in A Square Configuration     

Zhu  Hong-jun  Liu  Wen-li  Wang  Jun-lei 《中国海洋工程》2021,35(6):891-904

Flow-induced vibration (FIV) of four separately mounted cantilever cylinders are experimentally investigated in a water flume. The four cylinders with top ends screwed vertically into a turntable platform are subjected to uniform flows with Reynolds number ranging from 3840 to 16520. A non-intrusive measurement with high-speed cameras is employed to simultaneously capture the time-varying in-line and cross-flow vibrations in the reduced velocity range of 3.0–12.9. Experimental results highlight the continuous adjustment of flow regime caused by the spatial-temporal alteration of cylinders. Consequently, the space-time varying flow interference contributes to the occurrence of multiple response frequencies. The transition from a dominant frequency to a broad-band response illustrates the enhancement of wake interference. The combination of wake flow interactions results in the irregular oscillation trajectories and the appearance of a response trough with the associated switching in vortex shedding mode. The dual-resonance phenomenon is observed in the four cylinders due to the complicated wake-structure interaction. The greatest mechanical energy possessed by the four cylinders in an in-line square arrangement is mainly resulted from the downstream cylinders, signifying the positive role of wake excitation in extracting hydrokinetic energy from ambient flow.

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Wind Farm Support Vessel Extreme Roll Assessment While Docking in the Bohai Sea     

XU Xiao-sen  Oleg Gaidai  Oleh Karpa  WANG Jun-lei  YE Ren-chuan  CHENG Yong 《中国海洋工程》2021,35(2):308-316

Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,it is important to study the safety of operation in random sea conditions during WFSV docking against the wind tower,while workers are able to get on the tower.Docking is performed by thrusting vessel fender against wind tower(an alternative docking way by hinging is not studied here).In this paper,the finite element software AQWA has been used to analyze vessel response due to hydrodynamic wave loads,acting on a specific maintenance ship under actual sea conditions.Excessive roll may occur during certain sea conditions,especially in the beam sea,posing a risk to the crew transfer operation.The Bohai Sea is the area of diverse industrial activities such as offshore oil production,wave and wind power generation,etc.This paper advocates a novel method for estimating extreme roll statistics,based on Monte Carlo simulations(or measurements).The ACER(averaged conditional exceedance rate)method and its modification are presented in brief detail in Appendix.The proposed methodology provides an accurate extreme value prediction,utilizing available data efficiently.In this study the estimated return level values,obtained by ACER method,are compared with the corresponding return level values obtained by Gumbel method.Based on the overall performance of the proposed method,it is concluded that the ACER method can provide more robust and accurate prediction of the extreme vessel roll.The described approach may be well used at the vessel design stage,while defining optimal boat parameters would minimize potential roll.  相似文献