地铁行车荷载作用下淤泥质黏土累积特性的试验研究

中国上海地区地铁隧道一般位于第④层淤泥质黏土层中,在地铁行车荷载作用下隧道周围土体变形引起隧道轴线沉降,有些区段隧道轴线沉降量已超过20cm,引起了一系列环境地质问题.本文以上海第④层原状淤泥质黏土为研究对象,通过室内循环三轴试验,模拟地铁运营过程中产生的振动荷载,研究荷载作用下上海淤泥质黏土的累积应变、孔隙水压力及再...     

Response of runoff to climate change in the area of runoff yield in upstream Shiyang River Basin,Northwest China: A case study of the Xiying River

The objective of this study was to analyze the response of runoff in the area of runoff yield of the upstream Shiyang River basin to climate change and to promote sustainable development of regional water resources and ecological environment. As the biggest tributary of the Shiyang River, Xiying River is the only hydrological station (Jiutiaoling) that has provincial natural river and can achieve long time series monitoring data in the basin. The data obtained from this station is representative of natural conditions because it has little human activites. This study built a regression model through identifying the characteristics of runoff and climate change by using Mann-Kendall nonparametric statistical test, cumulative anomaly, and correlation analysis. The results show that the average annual runoff is 320.6 million m³/a with the coefficient of variation of 0.18 and shows slightly decrease during 1956–2020. It has a significant positive correlation the average annual precipitation (P<0.01). Runoff is sensitive to climate change, and the climate has becoming warm and wet and annual runoff has entering wet period from 2003. Compared to the earlier period (1955–2000), the increases of average annual temperature, precipitation and runoff in recent two decades were 15%, 9.3%, and 7.8%, respectively. Runoff in the Shiyang River is affected by temperature and precipitation among climate factors, and the simulation results of the runoff-climate response model (R = 0.0052P ? 0.1589T + 2.373) indicate that higher temperature leads to a weakening of the ecological regulation of surface runoff in the flow-producing area.     

Subsurface thermal and hydrothermal characterization based on geothermal resources map, drill hole thermal gradients, Curie point depths and hypocenter distribution — Examples of Tohoku district, Japan

Subsurface thermal structure in Tohoku district are characterized by existing data such as geothermal resources maps, drill hole thermal gradients, Curie point depths and hypocenters distribution maps. The collected data are registered in a database system, then, compared in plan view, cross-section and bird's-eye pictures. The comparison indicates that subsurface temperatures extrapolated from drill hole thermal gradients are generally concordant to the Curie point depth, assumed to be 650 °C. Tohoku district is generally divided into 5 type areas; fore arc lowland, fore arc mountain country, Quaternary volcanic terrain, back arc lowland and back arc mountain country. The surface thermal manifestations in Quaternary volcanic terrain are mainly controlled by the magma chambers as heat sources, while, surface thermal features such as hot springs in non-volcanic areas are controlled by degrees of heat flows, and hydrothermal flows in permeable Cenozoic formations and along permeable fault zones.     

瓦斯突出地球物理场的响应特征

研究了瓦斯突出地球物理场的电磁波和弹性波响应特征,其响应是构成瓦斯突出地球物理场的介质条件所表现出来的。关键层应力墙瓦斯突出机理认为,瓦斯突出煤层由关键层和伴随层构成。关键层和伴随层在空间的分布规律和相互作用体现在物理场的差异上,把关键层（或瓦斯突出煤体）作为地球物理场中的异常体进行研究是可以利用地球物理方法识别的。突出地球物理场响应特征的研究为从地球物理研究瓦斯突出预测理论和方法提供了科学思路。     

开都河中游地区雪岭云杉林上下限树轮宽度对比及其气候响应分析

利用开都河流域中段采集的雪岭云杉树芯样本,采用研究区域森林上下限2个采样点的树轮宽度年表,分析该地区两个树轮宽度年表的基本特征,建立与气象因子的关系模型,探讨树轮宽度生长与北大西洋涛动的关系。结果表明：（1）森林上限树木生长的一致性要强于森林下限,并且上限树轮宽度年表可能含有更多的气候信息;（2）森林上、下限树轮宽度年表在全频域、高频域及低频域上均存在显著正相关;（3）森林上、下限树轮宽度年表的气候响应结果基本一致,均表现出对上年9月至当年3月的逐月平均气温呈显著正相关,且均与上年12月的平均气温相关最高。树轮宽度年表与气象因子关系的模拟结果也证明了上年9、12月份和当年2、3、4月份的月平均气温与研究区树轮宽度生长间的密切关系;（4）研究区域树轮宽度生长与冬季北大西洋涛动指数的变化趋势较为一致。     

地下地震动频谱特点研究

本以美国加州强震观测计划(CSMIP）的6个岩土工程台阵的429条地表和地下地震动程为数据基础,按照各台阵场地土层分布情况将台阵分为七层和“上层／基岩”两类。对于同一类场地,将其中的各次地震,按照震级的大小将其分为三类;对于同一类地震,首先计算各地震的水下分量5％阻尼的反应谱以及相应的标准反应谱,并得到各深度测点相对于最深处测点的反应谱比值,分析比较两类场地下各深度反应谱的特点,另外,傅里叶谱也是本分析的一部分,通过对不同深度地下地震动的反应谱和傅氏谱的比较,得到了一些较有意义的结论,以供工程参考。     

铅橡胶复合阻尼器的性能试验研究

介绍作者提出的铅橡胶复合阻尼器的构造与耗能原理，通过不同形状，不同大小铅心的8个铅橡胶复合阻尼器的循环荷载试验，研究了频率、应变幅值、循环次数、铅芯直径、竖向压力等对铅橡胶复合阻尼器的影响规律。研究结果表明，铅橡胶复合阻尼器工作性能稳定，耗能性能和抗疲劳性能好。     

AP1000核电厂模型基底隔震振动台试验研究

为研究AP1000核电厂基底隔震性能,设计了缩尺比为1/40的AP1000核电厂模型结构,进行了AP1000核电厂模型基底隔震振动台试验。试验中采用铅芯橡胶隔震支座进行隔震,并选取RG1.60人工波、El Centro波和Kobe波作为地震动输入。本文从加速度响应、楼层加速度反应谱、加速度峰值放大系数、减震率等方面对隔震与非隔震核电厂结构的地震响应特性进行了研究。试验结果表明:隔震能明显减小上部结构水平向加速度响应和加速度反应谱峰值,而在隔震频率处隔震模型加速度反应谱有所增加;隔震模型由于摇摆效应在隔震频率处的水平向楼层加速度反应谱随楼层高度的升高先减小后增大;在三向输入地震动作用下,隔震和非隔震AP1000模型各楼层在竖向基频附近的竖向加速度反应谱较竖向输入的地震动放大较为明显。     

ZP-1型钻杆疲劳试验台

简述了ＺＰ－１型钻杆疲劳试验台的试验原理、主要技术性能参数和设计指导思想，并着重介绍了试验台机械传动系统和加载系统的组成、设计要点及试验台的试验情况。     

不同土壤湿度条件下绿洲边界层特征的敏感性试验

应用NCAR的非静力平衡中尺度数值模式MM5V3．6,设计了三种不同土壤湿度对金塔绿洲边界层的特征影响的敏感性试验。结果表明：土壤灌溉后地表温度和气温升温率较灌溉前有所减小。土壤湿度越大,绿洲温度越低,绿洲的“冷岛效应”越显著。绿洲灌溉后地面感热通量较灌溉前偏低,潜热通量比灌溉前高;土壤湿度越大,这种差异越显著。土壤湿度为0．35时,绿洲能够很好地表现绿洲特性,维持其自身的发展。绿洲边界层高度在灌溉前后有很大的变化。随着土壤湿度的增加,绿洲的边界层高度逐渐降低。这种较低的边界层对绿洲起到了保护作用,它将绿洲的能量与水分保存任较低的边界层中,促进了绿洲的进一步维持和发展。