唐山地震的非均匀错动模型──水准资料的反演结果     

孟国杰  于莉  高锡铭 《大地测量与地球动力学》1995,(2)

从地震矩张量的理论和点源的垂直位移公式出发，通过离散化地震矩密度，得到了用水准资料反演断层非均匀破裂的有限元模型。利用唐山地震前后的水准资料，采用非负限制的梯度方法反演了唐山地震的非均匀破裂，发现唐山地震的破裂主要是由两部分组成的，其中最大点滑动量为９．９０ｍ。计算得到地震矩为１．５×１０（２２）Ｎ·ｃｍ，说明唐山地震前后一年内的垂直形变是同震变化。  相似文献   

Turbulent Variance Characteristics of Temperature and Humidity over a Non-uniform Land Surface for an Agricultural Ecosystem in China   总被引：2，自引：0，他引：2  

高志球  卞林根  谌志刚  张佳华 《大气科学进展》2006,23(3):365-374

This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass (10% of area), beans (15%), corn (15%) and rice (60%). Under unstable conditions, the standard deviations of temperature and water vapor density (normalized by appropriate scaling parameters), observed by a single instrument, followed the Monin-Obukhov similarity theory. The similarity constants for heat (CT ) and water vapor (Cq) were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations (20% or 30% at most) of the similarity “constants” may be within the expected range of variation of a single instrument from the generally-valid relations.  相似文献   

流动型态对曼宁糙率系数的影响研究   总被引：7，自引：0，他引：7  

何建京  王惠民 《水文》2002,22(6):22-24,53

根据明渠水流流动型态的概念,通过对实验资料的分析,得到均匀流时糙率系数随水深增加而减小,形成M1型水面线的非均匀流时糙率系数随水深、水力坡度的增大而增大的规律。提出的糙率系数的二步计算法,可以解决因非均匀流水深沿程变化,难以建立糙率系数与水深关系的困难,为在水力计算中修正糙率系数提供了依据。  相似文献   

流体饱和多孔隙垂向非均匀固体的弹性波传播理论     

董连芝  王宝昌 《吉林大学学报(地球科学版)》1997,(2)

建立含有可压缩粘滞流体的多孔隙垂向非均匀弹性固体内之应力波传播理论。论述了其中的一个问题。即当Ｐｏｉｓｅｕｉｌｌｅ流动假设成立的低频率范围且流体与固体的质量密度可相比拟（例如含水饱和岩石之类）时，流体与固体间虽有相对运动但无摩擦的情形。在一定的近似条件下，可以存在两类膨胀波和一类旋转波，它们都存在频散  相似文献   

非均匀B样条函数的最小二乘法在GPS水准拟合中的应用     

王建雄  王腾军 《测绘科学》2007,32(3):65-66

最小二乘数据拟合方法的全局性较好,而非均匀B样条函数又具有良好的局部性,因此非均匀B样条最小二乘的稳定性及数值精度都能够得到有效的保证。本文根据已知点的GPS大地高和正常高,用非均匀B样条最小二乘法对GPS高程异常曲面进行拟合。实例计算结果表明,其高程转换精度达到四等结合水准精度,能够满足大比例尺测图的要求。  相似文献   

非一致地震激励地下综合管廊振动台模型试验研究(I)——试验方法     

史晓军  陈隽  李杰 《地震工程与工程振动》2010,30(1)

针对浅层软土中埋设的矩形截面地下综合管廊进行了非一致地震激励下的振动台模型试验研究。作为首个此种类型结构非一致激励的振动台试验工作,本文主要介绍试验方法,重点包括试验方案设计、开洞试验模型箱与模型结构设计,根据试验的特殊要求而开发的土体滑移传感器和地下结构接头位移测量装置,以及人工合成输入地震波动时程的方法与步骤。上述试验设计方法可供今后类似试验工作参考。试验结果分析及数值模型验证结果将在后续系列论文中介绍。  相似文献   

Study on 3D simulation of wave fields in acoustic reflection image logging     

《中国科学D辑(英文版)》2008,(Z2)

The borehole acoustic reflection imaging logging is a newly developed acoustic logging method that has attracted many interests. These converted and reflected waves for imaging are usually mixed up with borehole guided waves and therefore difficult to be clearly identified. To improve the downhole tool design and develop more sophisticate data processing and interpretation algorithms,studies on precisely numerical modeling of the wave fields in the acoustic reflection imaging logging are neces-sary and critical. This paper developed a parallelized scheme of 3D finite difference (3DFD) with non-uniform staggered grid and PML absorbing boundary to simulate the acoustic wave fields in isotropic and anisotropic formations. Applications of this scheme to the typical cases of isotropic and anisot-ropic formations and comparison with the results from published analytical solutions have demon-strated the validation and efficiency of the scheme. Higher accuracy and lower computation cost (3.5 times faster than the conventional schemes) have been achieved with this scheme for modeling such a complex wave fields of 60 dB dynamic range with higher frequency (10 kHz). This simulating program provides a quantitative analytical means for studying acoustic reflection imaging tool and development of the data processing and interpretation methods.  相似文献   

求解二维弹性半空间散射问题的波函数组合法     

姚虞  刘天云  张建民 《地震工程学报》2013,35(1):109-113

提出了一种新的波函数组合法,将体波与面波特征函数组合求解不规则河谷地形在不同波型以不同角度入射的非一致位移输入问题.新方法严格满足不规则河谷散射表面自由条件,克服了目前波函数函数展开法不能完备表达二维不规则地形散射问题的缺点.数值算例表明波函数组合方法具有精确、稳定、计算量小的特点,可以应用于结构-地基动力相互作用的非一致输入问题.  相似文献   

Richardson Number in a Moist Atmosphere and Its Application in the Analysis of Heavy Rainfall Events          下载免费PDF全文

ZHAO Yu  CUI Xiaopeng  GAO Shouting 《Acta Meteorologica Sinica》2010,24(1):95-103

To better describe the stability of a moist atmosphere,a new Richardson number,the Richardson number in a non-uniformly saturated moist atmosphere(Ri~*),is defined in this paper.Ri~* is the same as the Richardson number(Ri) except that the generalized potential temperature introduced by Gao et al.in 2004 is used to calculate the Brunt-Vaisala frequency.Then,with outputs from simulations of two heavy rainfall events,Ri~* is applied to diagnosing instabilities of rainfall areas.The results show that convec...  相似文献   

高压深井试气期间裸眼井壁稳定性分析     

陈军海  陈勉  金衍 《地质力学学报》2012,18(4):433-439

高压深气井裸眼试气期间,由于井内液柱压力较低,不能很好地支撑井壁,裸眼段可能发生井壁坍塌。在非均匀构造应力作用下井壁周围地应力分布的基础上,考虑井壁周围地层温度变化引起的热应力场和高压流体渗流引起的渗流应力场,并结合Mohr-Coulomb准则,可以确定防止高压深井试气期间井壁坍塌的井内当量流压,依此指导垫液、压井液的密度和高度,可确保测试工作顺利进行。   相似文献