软土深基坑支护技术中的若干土力学问题   总被引：7，自引：3，他引：7  

高大钊 《岩土力学》1995,16(3):1-6

评述了软土深基坑支护结构的现有设计方法，分析了墙的刚度和位移对土压力分布的影响，讨论了地下水对侧压力计算的影响、设计参数的测定与选取以及有限元计算中的一些问题，最后对支护结构的安全评价提出了建议。  相似文献   

SSQ-1 Digital Tape Recording Horizontal Pendulum Tiltmeter     

Hu Zhu  Hai-Ying Feng  Fa-Cheng Gao  Zhong-Guo Tang  Biao Ouyang 《地震学报(英文版)》1993,6(4):1031-1039

The SSQ-1 Digital Tape Recording Horizontal Pendulum Tiltmeter is an instrument of high sensitivity to detect the changes of ground tilt. It uses a quartz horizontal pendulum held by Z?llner bifilar suspension to sense vertical displacement, the eddy-current transducer on the pendulum converts its displacements into electric signals. Then a microcomputer is used for data acquisition and printing as well as digit tape recording. And at the same time, a filtering pen recorder is used for visible recording. The scale value of the instrument is calibrated by computer using the known tilt angle of the bulging plate — mercury cup. The scale value is 0.3–0.5 m(″)/mV. The following are the testing results for the earth tide observation obtained from the east-west component at Baijiatan Seismic Station, Beijing: r(O₁): 0.6490±0.0179 α(O₁): −3.83°±1.58° r(K₁): 0.8049±0.0128 α(K₁): 1.40°±0.90° r(M₂): 0.6699±0.0040 α(M₂): −0.27°±0.34° r(S₂): 0.7316±0.0075 α(S₂): 2.83°±0.58° r(M₃): 0.8497±0.0964 α(M₃): 1.61°±6.51° The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 353–359, 1993. In this work also participated Mr. Huai-Wen PAN and Wei-Jin ZHANG. And we here give special thanks to Yun-Zao XI, Qin-Wen XI, Bo-Xong TANG, Yi-Hui CHEN and An-Xu WU for their kind help in the development and test of the instrument. This paper is translated by Mr. Zhong ZHENG.  相似文献   

风廓线雷达水平风数据质量控制     

陈中钰  杜冰  刘康 《气象科技》2020,48(6):801-807

基于九龙站风廓线雷达实时水平风数据制定了水平风数据的质量控制方法，首先求取中位数水平风场，其次构建实际观测风场和中位数风场的差值序列，然后求取差值序列的均方差，再根据差值均方差得到质控判别式，最后试验求取质控判别式中的质控阈值。通过对九龙站2017年风廓线雷达水平风数据质量控制发现，实测风向数据有2044185个，25721个没有通过质控，未通过质控的风向数据占总观测的比例是1.258%，风向数据在近地层通过质控的数据最多，随高度增加通过质控的数据量有所下降。实测风速数据有2044185个，18296个没有通过质控，未通过质控的风速数据占总观测的比例是0.895%，风速数据在2000～4000 m出错的最少，近地层次之，4500～7000 m出错的数据最多。质控后风廓线雷达和探空观测风数据的均方根误差减小，相关系数增加，风向数据质量在500～7000 m提升明显，风速数据在1500～8000 m之间提升明显。  相似文献   

水平荷载作用下群桩相互作用的弹塑性数值分析   总被引：5，自引：0，他引：5  

周洪波  杨敏  茜平一 《水文地质工程地质》2003,30(3):29-35

本文利用三维弹塑性有限元法对水平荷载作用下群桩基础特性进行了分析,讨论了群桩基础水平荷载作用下的承载性状和破坏机理,并探讨了桩距、桩数、桩长、桩径和土质各种因素对群桩效应的影响,指出桩距和桩数是影响群桩效应的主要因素。  相似文献   

Recent crustal horizontal movement in the Chinese mainland   总被引：1，自引：0，他引：1  

黄立人  王敏 《地震学报(英文版)》2000,13(3):273-279

IntroductionSupportedbytheNationaIClimbingProject"RecentCrustalMovementandGeodynamicResearch",acrustalmovementmonitoringnetworkdistributedinChinesemainlandhasbeenmeasuredfortWotimesinl994andl996.Thenetconsistsof22stationsthatarelocatedonsev-eralmajortectonicblocksinChinesemainland.ExceptNanchongstationwhichwasdestroyedatsometimebetWeenl994and1996andre-settledinl996,alltheother2lstationswereoccupiedfortwotimes.BasedontheresuItSobtainedfromcarefulpre-processingofGPSobservations,therecent…  相似文献   

Modelling peak accelerations from earthquakes   总被引：1，自引：0，他引：1  

Debbie J. Dupuis  Joanna Mills Flemming 《地震工程与结构动力学》2006,35(8):969-987

This paper deals with the prediction of peak horizontal accelerations with emphasis on seismic risk and insurance concerns. Non‐linear mixed effects models are used to analyse well‐known earthquake data and the consequences of mis‐specifying assumptions on the error term are quantified. A robust fit of the usual model, using recently developed robust weighted maximum likelihood estimators, is presented. Outlying data are automatically identified and subsequently investigated. A more appropriate model accounting for the extreme value nature of the responses, is also developed and implemented. The implication on acceleration predictions is demonstrated. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Study of a model for correcting the effects of horizontal advection on surface fluxes measurement based on remote sensing     

《中国科学D辑(英文版)》2006,(Z2)

As well known, the methods of remote sensing and Bowen Ratio for retrieving surface flux are based on energy balance closure; however, in most cases, surface energy observed in experiment is lack of closure. There are two main causes for this: one is from the errors of the observation devices and the differences of their observational scale; the other lies in the effect of horizontal advection on the surface flux measurement. Therefore, it is very important to estimate the effects of horizontal advection quantitatively. Based on the local advection theory and the surface experiment, a model has been proposed for correcting the effect of horizontal advection on surface flux measurement, in which the relationship between the fetch of the measurement and pixel size for remote sensed data was considered. By means of numerical simulations, the sensitivities of the main parameters in the model and the scaling problems of horizontal advection were analyzed. At last, by using the observational data acquired in agricultural field with relatively homogeneous surface, the model was validated.  相似文献   

多股水平淹没射流水力特性的影响因素研究   总被引：1，自引：0，他引：1       下载免费PDF全文

李艳玲  华国春  张建民  杨永全 《水科学进展》2006,17(6):761-766

采用数值模拟和模型试验相结合的方法,分析了水股分层、坎高、出口体型和跌坎形式等因素对多股水平淹没射流的流态稳定性和水力特性的影响。研究表明,多股多层水平淹没射流较单层多股水平淹没射流流态稳定性好、临底流速低、消能率高,是一种高效的新型消能方式。结合试验结果,提出中孔泄槽以等宽或微收缩为宜、表中孔最优坎高差应大于中孔水流的主流水深、跌坎形式的选择应结合具体工程特点等建议。  相似文献   

大气折光对水平角测量影响及对策研究   总被引：2，自引：0，他引：2  

张正禄  邓勇  罗长林  梅文胜 《武汉大学学报(信息科学版)》2006,31(6):496-499

通过测量实践和试验,分析了大气折光对特高精度边角测量的影响,指出旁折光是水平角测量误差的主要来源,而对边长的影响甚微;同时,边角网中水平角测量时起始方向的选择十分重要,提出了采用测量机器人作自动观测的一种起始方向确定和质量检查方法;并阐述了特高精度边角网布设和施测中为减少大气折光影响的一些对策.  相似文献   

非静力滞弹性模式中水平分辨率与垂直分辨率的协调性初探     

刘宇迪  田福厚  张亮  侯志明 《热带气象学报》2006,22(5):473-478

为了理论上研究非静力滞弹性模式中水平分辨率与垂直分辨率之间的搭配问题，以线性斜压滞弹性方程组为出发方程，导出解析的频散方程、水平群速方程和垂直群速方程，同时在最优三维网格C／CP下进行离散，也导出频散方程、水平群速方程和垂直群速方程，然后用图示的方法，比较了在不同的水平和垂直格距下模拟解析解所产生的误差。结果表明：当垂直格距和水平格距相当时，在C／CP网格上对惯性重力波的频率、水平群速和垂直群速都能较好地模拟，产生的相对误差均在5％以下。  相似文献