频率域中有限元素法的探讨     

Yang Baojun 《吉林大学学报(地球科学版)》1986,(4)

本文指出了用拉普拉斯变换处理有限元方程和用富里叶变换所得到的结果是等价的。从物理方面讨论了频率域有限元的局限性。  相似文献   

施力方式对半地堑反转构造变形特征影响的物理模拟实验研究   总被引：13，自引：5，他引：8  

马宝军  漆家福  于福生  杨雪 《大地构造与成矿学》2006,30(2):174-179

根据断层的上下盘施力方式的不同设计了两组实验,以探讨在刚性边界条件下的半地堑反转构造的变形特点。实验结果表明(1)在自由边界基底驱动下形成的盆地反转规模较大,刚性边界处会沿原断层发生反转,而在自由端断层不会反转,但会形成深部低角度逆冲滑脱断层;(2)在刚性下盘侧向驱动下很小的挤压量就会形成盆地的反转,但是反转的范围较小,随着原设边界断层的角度由小到大,盆地内的断层会发生由刚性边界处单侧发生反转到两侧边界断层发生近对称式反转的变化;(3)实验结果证实了辽河坳陷西部凹陷反转构造是在刚性下盘为主动盘挤压变形下形成的。  相似文献   

黄河小浪底斜坡变形的“反迭瓦”式构造机制研究     

王宝军  李清波 《高校地质学报》1999,5(1):100-104

针对小浪底地区斜坡中普遍发育的“返迭瓦”式构造,结合该区的工程地质条件,对其成因机制进行分析。提出了“反迭瓦”式构造的形成是由于边坡蠕变形的结果,并非造成滑坡的原因。  相似文献   

张家口-渤海断裂带西段及中西段b值时空扫描   总被引：2，自引：2，他引：0  

段美芳  陆丽娜  李莹甄  李宝君  杨明  贾建鹏 《震灾防御技术》2018,13(1):138-148

张家口-渤海断裂带作为华北平原地区重要的活动断裂带,地震活动频繁,是我国地震监测预测重点区域之一。本文选取该断裂带西段及中西段1970-2016年的地震目录,采用最大似然法进行时间扫描,分析显示研究区b值为0.28-1.52,其随时间变化的特点是在大地震发生前降至最低,震后逐渐恢复;研究区空间扫描结果显示,该区b值的平均值为0.93,其中怀安-万全盆地北缘断裂和蓟运河断裂平均b值较低,反映该区域应力水平较高。综合以上结果,本次研究揭示出研究区地震危险性的时间和空间差异,为对研究区地震危险性评价提供基础数据。  相似文献   

Impacts of headcut height on flow energy,sediment yield and surface landform during bank gully erosion processes in the Yuanmou Dry‐hot Valley region,southwest China          下载免费PDF全文

Baojun Zhang  Donghong Xiong  Guanghui Zhang  Su Zhang  Han Wu  Dan Yang  Liang Xiao  Yifan Dong  Zhengan Su  Xiaoning Lu 《地球表面变化过程与地形》2018,43(10):2271-2282

To quantify the changes in flow energy, sediment yield and surface landform impacted by headcut height during bank gully erosion, five experimental platforms were constructed with different headcut heights ranging from 25 to 125 cm within an in situ active bank gully head. A series of scouring experiments were conducted under concentrated flow and the changes in flow energy, sediment yield and surface landform were observed. The results showed that great energy consumption occurred at gully head compared to the upstream area and gully bed. The flow energy consumption at gully heads and their contribution rates increased significantly with headcut height. Gully headcuts also contributed more sediment yield than the upstream area. The mean sediment concentrations at the outlet of plots were 2.3 to 7.3 times greater than those at the end of upstream area. Soil loss volume at gully heads and their contribution rates also increased with headcut height significantly. Furthermore, as headcut height increased, the retreat distance of gully heads increased, which was 1.7 to 8.9 times and 1.1 to 3.2 times greater than the incision depth of upstream area and gully beds. Positive correlations were found between energy consumption and soil loss, indicating that energy consumption could be used to estimate soil loss of headcut erosion. Headcut height had a significant impact on flow energy consumption, and thus influenced the changes in sediment yield and landform during the process of gully headcut erosion. Headcut height was one of the important factors for gully erosion control in this region. Further studies are needed to identify the role of headcut height under a wide condition. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

南海北部阳江‒一统暗沙断裂带与新近纪岩浆活动     

蔡国富  张向涛  彭光荣  吴静  柳保军  白海军  李振升  马晓楠  李三忠  索艳慧 《大地构造与成矿学》2021,45(1):40-52

阳江?一统暗沙断裂带是南海北部珠江口盆地极其重要的中?新生代构造带和转换带.基于钻井资料和大范围、高密度的二维、三维地震资料,本文初步揭示阳江?一统暗沙断裂带走向为NW-NWW向、宽约30 km,沿着断裂走向从陆架至洋陆边界断裂带可分为北?中?南三段,断裂在新生代选择性活化,具有多重走滑断裂叠合和基底岩浆底辟强烈等特点...  相似文献   

NCDSN台站地震监测系统实时监视软件   总被引：3，自引：3，他引：0  

马宝君  赵谊  崔东源  马莉  李云龙 《地震地磁观测与研究》2006,27(2):89-92

阐述NCDSN台站连续波形数据断记问题的一种解决办法,软件安装及其使用方法,方法简便易行,便于推广。  相似文献   

深水沉积研究前缘问题   总被引：27，自引：0，他引：27  

庞雄  陈长民朱明何敏  柳保军申俊 连世勇 《地质论评》2007,53(1):36-43

深水沉积研究经历了50年,争论也持续了50年。从浊流及鲍玛序列开始,随着对浊流定义的过分使用,到今天对鲍玛序列作为浊积岩相序及相关的扇模式普遍持否定态度,深水沉积研究经历了一个认识的旋回。主要问题和争论的焦点是：是否所有深水砂岩都是浊流成因,鲍玛序列能否代表浊积岩相序;是否所有的深水扇水道下方都能形成席状的、平行的、加厚的、具有丘状外形的浊积砂岩沉积;是否可以利用地震方法识别深水扇的砂岩储层。对“浊流”概念的过分使用把深水扇模式内几乎所有深水沉积都解释成浊流成因,导致了曾经为之建立模式的学者纷纷撰文抛弃原有扇模式。深水沉积研究面临着对过往认识的否定和如何建立新的理论模式。尽管浊流及相关的深水扇模式研究走向穷途末路,石油工业却从浊流理论和相关模式中获得了许多油气发现,勘探家们仍然希望通过这些模式寻找更多的油气,科学理论和应用出现了分化。对深水沉积过程和流态的认识及沉积模式的建立是当今深水沉积研究的难点,实现深水砂岩储层的有效预测是深水沉积研究的主要目的。我国深海油气勘探在即,深水沉积的科学问题同样不可逾越。  相似文献   

The lithosphere structure of Northeast China     

Xingzhou Zhang  Baojun Yang  Fuyuan Wu  Guoxing Liu 《Frontiers of Earth Science》2007,1(2):165-171

The lithosphere of northeastern China is composed of the Erguna, Xingan, Songnen, Jiamusi blocks and Mesozoic Wandashan accretionary complex from west to east. Nd isotope model ages indicate that the Xingan and Songnen blocks have the same Nd model ages ranging from 500 to 1 000 Ma. These are obviously younger than those of the Jiamusi block (1 500–2 000 Ma) and the Erguna block (1 500–1 700 Ma), reflecting the different evolutions of individual blocks in the early times. Geochemical tracing analysis shows that the Nd model ages of Paleozoic supercrustal rocks in the four blocks are dominantly Mesoproterozoic, while those of Mesozoic granites are mainly Neoproterozoic. It is shown that the crust ages of the region are characterized by being younger in the lower part and older in the upper part. The Os isotope analysis also indicates that the lithosphere mantle of the region is characteristic of a younger age. The P-wave velocities of the region show more complicated structures in lithosphere and asthenosphere. First of all, notably different from traditional concept of the seismic lithosphere, the low velocity zone of the lithosphere beneath the region has no persistent and continuous top interface which is highly varied in depth and intersected with the high velocity layers, forming sharp velocity discontinuities beneath major tectonic belts, even up to the Moho beneath some tectonic units. But the bottom interface of the low velocity zone is relatively persistent, occurring at a depth of 230–240 km. Another feature is that the lithosphere is characterized by an “overpass type” velocity structure vertically, in which the contoured velocity is distributed in the NE trending within the crust, in a nearly NS trending in the lithosphere mantle from a depth of 45 to 90 km, in a nearly EW trending in the upper part of the asthenosphere from 90 to 170 km and in a ring-like distribution with a diameter of about 300 km in the lower part of the asthenosphere from 170 to 240 km. The P-wave velocity is progressively increasing from 240 to 400 km.  相似文献   

雨滴谱分布函数的选择:M-P和Gamma分布的对比研究   总被引：6，自引：2，他引：6       下载免费PDF全文

郑娇恒  陈宝君 《气象科学》2007,27(1):17-25

M-P分布和Gamma分布是常用的两种雨滴谱分布函数。利用PMS GBPP-100型雨滴谱仪2003年7-8月在沈阳观测的雨滴谱资料,采用阶矩法对两种分布函数进行拟合,对比分析两种分布函数对谱及数浓度、雨强和雷达反射率因子的拟合效果。结果表明,在降水较弱、小滴偏少时Gamma分布会低估小滴,而M-P分布会高估小滴;降水强时,两种分布均低估小滴。M-P和Gamma分布对数浓度、雨强和雷达反射率因子这些特征量的拟合效果,在降水较强时差异很小,在降水较弱时差异较大。Gamma分布的代表性更好。此外,还讨论了两种分布的参数和雨强的关系。  相似文献