Regression Formulations for the Stress at Hot Spot of Multiplanar Tubular DT Joints

- Stress concentration analysis of multiplanar tubular DT joints plays an important role in the fatigue design of offshore platforms. A semi-analytic method for stress analysis under the condition of any loads is briefly introduced in the paper. Nineteen multiplanar tubular DT joints with one of two braces of the same dimension subjected to axial loads and out- of- plane bending moments are computed for parametric stress analysis by using the present method. The influence of geometrical parameters on the stresses of multiplanar tubular DT joints is discussed and compared with corresponding uniplanar T joints. The regression formulae for the stress at hot spot of multiplanar DT joints are found by modification of SCF of corresponding uniplanar T joints. The parametric formulae for the maximum stress by superposition. Finally, the influences of stiffening effect and load-interaction effect on the maximum stress of DT joints are discussed.     

INVESTIGATIONS ON EROSIONAL PROCESSES OF COHESIVE SEDIMENT USING AN IN-SITU MEASURING DEVICE

I.INTRODUCTIONToconstructanidealmeasuringdeviceforin-situstUdiesincomparisontolaboratorydeVicesastrongeremphasishastobesetonthehandlingoftheSystemandtheresistanceunderwater,whichaughtbethereasonwhynotmanyapproachesonrealin-situinvestigationwerecaaccedoutlately.Sincetheedupandtheconstructionseemtodemandahigheramountofcostsandeffort,quasiin-siamstudieswerecAnedoutrefetringtoanundisturbedsedimentsampledrawnfromthesedimentbedoutofthewaterintothesamplingchamberofameasuringdevice.Evenifthisisa…     

内蒙古库伦旗拉民稿金多金属矿化区成矿地质特征及找矿方向

拉民稿金多金属矿化区位于通辽市库伦旗西南部拉民稿地区,根据野外地质调查结果,在矿区圈出金多金属矿化带四条（PS1、PS2、PS3、PS4）,采样含金品位一般为（0.11-7.48）×10-6,最高为13.56×10-6,含银最高品位为92.5×10-6。钻孔中圈出矿体可分三类：灰岩（见黄铁矿化、硅化）、板岩（见黄铁矿化...     

The Stress Concentration of Multiplanar Tubular Joints of Offshore Structure

- The formulation for the stress concentration matrix of multiplanar tubular joint with braces subjected to combined load is established in this paper. The formulations for SCF values of multiplanar tubular joints are compared with those by Wordsworth and Efthymiou. The stiffening effect and load-interaction effect are discussed. A spatial offshore jacket with braces subjected to combined load is computed as a numerical example. The maximum stress of each multiplanar tubular joint and its location are found through SCF matrix. Finally, the difference between the maximum stresses of multiplanar tubular joints and their corresponding uniplanar tubular joints are discussed.     

内蒙古额济纳旗千条沟铜多金属矿化区成矿地质特征及找矿方向

千条沟铜多金属矿区位于内蒙古自治区额济纳旗千条沟北约6公里,行政区划隶属阿拉善盟额济纳旗所在地达来呼布镇。南东距额济纳旗政府所在地约120公里。工区位于北山山系的东北边缘,六陀山横担在图幅中部。大地构造位置属天山—阴山纬向构造体系的中段。工区地层主要以奥陶系粉砂岩和二叠系板岩为主,岩浆岩以闪长岩、斜长花岗岩、花岗斑岩、花岗岩为主,区内构造受近东西向冲断深大断裂和区域六驼山复背斜影响,主要为次级羽状断裂和张性断裂,多被后期岩浆侵入岩及后期石英脉充填,在工区南西部斜长花岗岩区,发现1号矿脉、2号矿脉、3号矿脉群、4号矿脉群,其地表矿化体均为石英脉,具较强孔雀石化,且肉眼可见铅矾,矿脉走向以南西-北东为主。总的分析,工区南西部为重点找矿区域,物探、化探、地质综合分析的结果都比较吻合,褶皱和断裂较发育,热液活动明显,矿脉品位较高,具有找到铜多金属矿床的成矿条件。     

深基坑变形监测方案设计及数据分析研究

结合某深基坑监测实践,探讨了基坑安全监测点的布设,并对支撑轴力和地下水位监测数据进行了深入分析,研究表明,混凝土持续的体积收缩以及在荷载下混凝土发生徐变被认为是影响轴力异常的最主要因素.对基坑工程监测实践有一定的借鉴意义.