大兴安岭南部二叠纪-三叠纪之交孢粉化石及古气候环境分析

大兴安岭南部巴林右旗幸福之路苏木查干布拉格村老龙头组（原幸福之路组模式）剖面首次发现孢粉化石18属21种,以Cyclogranisporites sp.,Alisporites parvus De Jersey,Alisporites circulicorpus Clarke,Sulcatisporites rhombicus Qu,Lueckisporites virkkiae R.Potonie et Klaus,Piceites sp.为主。通过典型属种对比,结合已发现的动植物化石、孢粉组合及同位素测年结果分析,确定幸福之路地区老龙头组的时代为晚二叠世-早三叠世,即二叠系-三叠系界限存在于这套陆相连续沉积内部。孢粉化石的亲缘母体以发育种子蕨纲和松柏纲的针叶植物为主,指示当时研究区处于暖温带的干旱-半干旱的古气候环境。     

Application of Random Process in Soil Profile Modeling

When using the random process in soil profile modeling, the stationary and ergodicity of thesoil properties in the profile must be tested. This paper describes a procedure for stationary and ergodicity testing. Numerical examples were given for demonstration. A log-cosine function is suggested to simulate the correlation function, which has been proved to be good for soil profile modeling.     

辽宁北部秀水盆地下白垩统义县组火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义

为查明秀水盆地烃源岩层位形成时代,对侵位到秀D1井义县组三段沉积地层中的次火山岩样品和地表发育的义县组火山岩样品,分别进行LA-ICP-MS锆石U-Pb测年,获得火山岩同位素年龄值为121.5±1.2~121.3±3.5 Ma,时代为早白垩世。通过与区域相同时代火山岩同位素年代学对比研究表明,秀水盆地火山岩形成时期为义县组末期火山活动。秀水盆地义县组末期火山岩年龄的确定,不仅确定了义县组末期火山岩形成的上限年龄（121.3 Ma）,同时也确定了秀水盆地主力烃源岩层位（义县组三段）的上限年龄（约121 Ma）。明确了义县组三段沉积层作为辽宁西北地区重要的油气勘探目的层系,为松辽盆地外围断陷盆地群油气勘探提供了新的目的层系。     

Prediction to the Efficiency of Soft Clay Sample Preparation with Vacuum Loading

Vacuum loading has been examined as a way of preparing uniformly consolidated soft claysamples.The facility and loading procedure are described in this paper.An analytical solution to the threedimensional consolidation equation is derived for estimating the degree of consolidation of the soil samplewith vacuum loading.The given example shows that the predicted degree of consolidation of a soft claybulk with vacuum loading is close to that measured in the consolidation process.     

Case study on pile running during the driving process of large-diameter pipe piles

The super-long and large-diameter steel pipe piles are often adopted for the construction of offshore oil platforms in deep sea. One constructability issue related to driving heavy pipe piles is the pile running. The term pile running refers to the quick penetration of a pile into the seabed as a result of its high self-weight and low resistance from the seabed. The unexpected pile running can cause the steel wire of the hammer to break or even the loss of the hammer. A case study of pile running at an oil platform is introduced in this paper. A simplified theoretical method is proposed to explain the mechanisms of the pile running in this case. A factor of friction degradation is proposed to calculate the dynamic skin friction from the static ultimate skin friction of surrounding soil. The comparisons between the predictions to the case history show that the proposed simplified method can be used to predict the pile running condition.     

往复荷载作用下软粘土中浅埋管道的稳定性的振动台模型试验研究

软粘土在波浪荷载作用下,可能发生强度软化,使埋设在软粘土层中的海底管道的受力状态或支撑条件发生变化,从而出现上浮或下沉的趋势,对管道的稳定性发生影响。本文通过在振动台上进行的模型试验来模拟当土性因动荷作用而发生变化时管道的稳定情况,对这个问题进行了探索,得出了一些规律性的认识,可供海底管道的设计者参考。     

Settlement and Stability Analysis on Soft Clay Under Cyclic Loading

The results of undrained cyclic triaxial tests on three types of clays are collected and a relationship among the accumulated strain, the initial stress state, cyclic stress in the soil, as well as the number of cycles is established based on the experimental data. With this relationship, a procedure is proposed for subsidence and stability analysis on soft clay under the action of cyclic loads.     

内蒙古科右中旗—突泉地区晚二叠世林西组碎屑岩LA-ICP-MS锆石U-Pb年龄及其地质意义

内蒙古科右中旗—突泉地区出露一套缺少化石、遭受接触变质作用的巨厚层碎屑岩,其先后被划归为早二叠世索伦组、晚二叠世林西组、下寒武统。取自该套地层砂岩样品的碎屑锆石LA-ICP-MS U-Pb定年数据表现为2个主要年龄区间:255~354Ma,峰值年龄为263Ma和283Ma;413~529Ma,峰值年龄为485Ma。另有5颗锆石的年龄值分别为625Ma、965Ma、1372Ma、1707Ma、1727Ma。263Ma的峰值年龄限定了该套地层的沉积下限应为晚二叠世,结合区域地层对比,认为是晚二叠世林西组。该地层年代为突泉盆地下伏第二低阻层为林西组的推断提供了年代学证据。     

冰（雪）晶生长微物理过程的风洞实验研究

该文简要介绍了（１）风洞实验研究的科学意义及应用前景；（２）冰（雪）晶增长微物理实验的研究的概况；（３）新研制的冰（雪）晶增长小型垂直过冷云风洞及其测试系统；（４）主要实验研究结果，包括风洞实验模拟出的冰（雪）晶，含水量对冰（雪）晶增长的影响，风洞中冰（雪）晶的运动方式，初始晶胚特性及运用实验结果指导象灾害的预测及防治。     

结构性吹填软土流变等时曲线研究

软土普遍存在结构性,结构性影响土体各种力学行为。对天津滨海新区结构性吹填软土进行三轴流变试验,通过对比分析原状土与重塑土流变等时曲线发现,结构性吹填软土流变等时曲线可分离为线性粘弹性变形、线性粘塑性变形与非线性粘塑性变形。在应力小于结构屈服应力时,流变等时曲线线刚度大;超过结构屈服应力时,伴随着土结构的破损,流变等时曲线线刚度逐渐减小,最终趋于一定值,与重塑土接近。结构性对流变等时曲线的影响主要集中在线弹性阶段,进入塑性阶段后影响较小。