Demonstration of spatial anisotropic deformation properties for jointed rock mass by an analytical deformation tensor     

《Computers and Geotechnics》2017

This paper develops a joint deformation tensor (JD), which considers all of the joint's mechanical and geometrical parameters that affect the deformability of the rock mass. The method based on JD (JD method) and an elastic deformation anisotropy index (EDAI) are deduced for estimating the spatial anisotropy deformation of a jointed rock mass. The numerical modeling and in situ true triaxial compressive experiments well verified the effectiveness of the EDAI and JD method for the rock mass containing one joint set, orthogonal joint sets or the rock mass containing any types of joint network with unity stiffness ratio.  相似文献   

A study on the Local Joint Flexibility (LJF) of two-planar tubular DK-joints in jacket structures under in-plane bending loads     

《Applied Ocean Research》2017

In the present paper, results of a parametric study conducted on the Local Joint Flexibility (LJF) of two-planar tubular DK-joints under In-Plane Bending (IPB) loads are presented. DK-joints are among the most common joint types in jacket substructure of Offshore Wind Turbines (OWTs). A total of 324 finite element (FE) analyses were carried out on 81 FE models under four types of IPB loading in order to investigate the effect of the DK-joint’s geometrical parameters on the LJF factor (f_LJF). Based on the results of parametric study, the factors leading to the LJF reduction were introduced. Generated FE models were verified using the existing experimental data, FE results, and parametric equations. The effect of the weld profile was also considered. The f_LJF in two-planar DK- and uniplanar K-joints were compared. Results indicated that the effect of multi-planarity on the LJF is quite significant and consequently the use of the equations already available for uniplanar K-joints to calculate the f_LJF in two-planar DK-joints may lead to highly under-/over-predicting results. To handle this issue, the FE results were used to derive a set of parametric equations for the prediction of the f_LJF in IPB-loaded two-planar DK-joints. The proposed equations were checked against the acceptance criteria recommended by the UK DoE and can be reliably used for the analysis and design of tubular joints in OWTs.  相似文献   

TURFs in the post-quake recovery: Case studies in Sanriku fishing communities,Japan     

《Marine Policy》2017

This study explored how Territorial Use Rights for Fisheries (TURFs) functioned during the recovery from the devastating tsunami disaster which struck the Sanriku region in 2011, with a focus on abalone harvest, which is the most profitable resource managed by TURFs. During the winter of 2011–2012, only 36 of 51 managing bodies could harvest abalones because of a great shortage of boats. Recourse degradation was also feared, and the harbors were badly damaged. Of 27 managing bodies whose harvesting methods were known, 22 harvested collectively. Abalones are traded at high price and harvesting them requires skill; hence, it has always been done individually and competitively; collective harvesting conducted during this season was therefore quite exceptional. Eighteen managing bodies also handled distribution of the harvest, adopting flexible measures according to each community's circumstances. The collective action ended immediately after the urgent shortage of boats was alleviated. The diversity of natural resources managed by TURFs, autonomy of the fishing communities fostered by their remoteness and the nested structure of TURFs’ resource management enhanced the resilience of the fishing communities.  相似文献   

2D numerical investigation of segmental tunnel lining under seismic loading     

《Soil Dynamics and Earthquake Engineering》2015

Segmental tunnel linings are now often used for seismic areas. However, the influence of segment joints on the segmental lining behavior under seismic loading has not been thoroughly considered in the literature. This paper presents a numerical study, which has been performed under seismic circumstance, to investigate the factors that affect segmental tunnel lining behavior. Analyses have been carried out using a two-dimensional finite difference element model. The proposed model allows studying the effect of the rotational joint stiffness, radial stiffness and the axial stiffness of the longitudinal joints. The numerical results show that a segmental lining can perform better than a continuous lining during earthquake. It has been seen that the influence of the joint distribution, the joint rotational stiffness, the joint axial stiffness, Young׳s modulus of the ground surrounding the tunnel, the lateral earth pressure factor and the maximum shear strain should not be neglected. Some important differences of the segmental tunnel lining behavior under static and seismic conditions have been highlighted.  相似文献   

Block Simulation of Multiple Correlated Variables     

Alexandre Boucher  Roussos Dimitrakopoulos 《Mathematical Geosciences》2009,41(2):215-237

Numerical representations of multivariate natural phenomena, including characteristics of mineral deposits, petroleum reservoirs and geo-environmental attributes, need to consider and reproduce the spatial relationships between correlated attributes of interest. There are, however, only a few methods that can practically jointly simulate large size multivariate fields. This paper presents a method for the conditional simulation of a non-Gaussian vector random field directly on block support. The method is derived from the group sequential simulation paradigm and the direct block simulation algorithm which leads to the efficient joint simulation of large multivariate datasets jointly and directly on the block support. This method is a multistage process. First, a vector random function is orthogonalized with minimum/maximum autocorrelation factors (MAF). Blocks are then simulated by performing LU simulation on their discretized points, which are later back-rotated and averaged to yield the block value. The internal points are then discarded and only the block value is stored in memory to be used for further conditioning through a joint LU, resulting in the reduction of memory requirements. The method is termed direct block simulation with MAF or DBMAFSIM. A proof of the concept using an exhaustive data set demonstrates the intricacies and the performance of the proposed approach.  相似文献   

对接穿越技术及其在钱塘江穿越的应用     

张跃武 《岩土钻凿工程》2009,(6):32-35

文中介绍了常见的人工交流磁场导向、交流磁靶导向、旋转磁铁导向及轴向磁铁导向等四种对接穿越技术的导向原理;并对钱塘江穿越工程导向孔对接穿越进行了简要阐述。  相似文献   

冬季热带太平洋和印度洋SSTA对大气协同作用的数值试验   总被引：3，自引：0，他引：3  

李永平  秦曾灏  孙照渤 《气象学报》1996,54(5):612-619

通过比较热带太平洋和印度洋典型分布的海表温度距平（ＳＳＴＡ）场以及热带西太平洋孤立海域ＳＳＴＡ对大气环流影响的数值试验结果，发现两者存在明显的差异，前者与观测事实一致，由此说明大气环流异常是热带太平洋和印度洋ＳＳＴＡ协同作用的结果。  相似文献   

感应-横向组合测井联合反演及多解性研究     

刘振华  林豪 《地球物理学进展》2001,16(1):47-55

电阻率测井反演问题解的局部收敛性和非唯一性增加了测井解释的难度，影响了实际的应用，把测量原理迥异的感应型和电流型测井结果联合起来反演，是减小这些影响的有效方法，利用经测井理论和反演技术，建立了适用感应－横向组合测井响应的联合演算法，研究了单一的横向测井反演的感应－横向联合反演的局部收敛性、非唯一性及解的偏差，结果表明，联合反演更有利于同时确定地层电阻率、侵入半径和侵入带电阻率，当初值地较大范围内变化时，反演结果均能在真值或真值附近收敛，改善了反演结果的局部收敛性，增加了反演结果的可信度，避免了差异较大乃至相互矛盾的解，现场实例证实了这一结论。  相似文献   

Towards a Virtual Asian－Pacific Seismological Network     

Zhu Chuanzhen  Chen Yuntai  Liu Ruifeng  Xu Lisheng  Wu Zhongliang 《中国地震研究》2002,16(3):298-303

Regional international cooperation in seismic data exchange and joint seismological analysis in the Asian-Pacific regions plays an important role in the reduction of earthquake disasters in these regions as well as the development of global seismology.Based on the up-to-date development of new technology and digital broadband seismology,we discussed the Asian seismological Commission(ASC) Proposal “Asian-Pacific Seismological Data Center“,We applied the concept of virtual seismological network(Ottemoeller and Havskov,1999) to the proposed ASC data exchange program.Based on the development of digital seismology,we in troduced a concept of “modern earthquake catalogues“which include not only location parameters and magnitudes as in the conventional earthquake catalogues but also new parameters of earthquakes such as CMT,radiated energy,STF,and earthquake rupture process,We recommended a webbased regional international data exchange program between the ASC members with the purpose of forming a virtual Asian-Pacific seismological network,and the interpretation and analysis of broadband digital seismic waveforms conducted at distributed“data centers“.  相似文献   

JRC快速测量技术   总被引：4，自引：1，他引：4  

杜时贵  杨树峰  姜舟  朱益军  万颖君 《工程地质学报》2002,10(1):98-102

在回顾粗糙度测量方法的基础上 ,从岩石节理的具体特点出发 ,研制了轮廓曲线仪和粗糙度尺 ,为节理粗糙度系数的统计测量提拱了一种快速测量手段。  相似文献