用接收函数方法研究上海地震台阵下地壳结构   总被引：1，自引：1，他引：0  

王俊菲  朱元清  王小平 《地震地磁观测与研究》2010,31(2):50-55

利用上海地震台阵16个台站记录的远震资料,采用接收函数线性反演方法,对台阵下的地壳速度结构进行研究,获得了研究区域内地壳厚度和地壳速度的分布特征。研究结果表明,研究区域Moho面深度约为33±2 km,Moho面深度基本不变,地幔顶部S波速度约4.4 km/s,地壳内没有发现明显的低速层。  相似文献   

Residual curvature migration velocity analysis for angle domain common imaging gathers   总被引：2，自引：0，他引：2  

Kai Zhang  Zhen-Chun Li  Tong-Sheng Zeng  Xiao-Chun Dong 《应用地球物理》2010,7(1):49-56

Pre-stack depth migration velocity analysis is one of the keys to influencing the imaging quality of pre-stack migration. In this paper we cover a residual curvature velocity analysis method on angle-domain common image gathers (ADCIGs) which can depict the relationship between incident angle and migration depth at imaging points and update the migration velocity. Differing from offset-domain common image gathers (ODCIGs), ADCIGs are not disturbed by the multi-path problem which contributes to imaging artifacts, thus influencing the velocity analysis. On the basis of horizontal layers, we derive the residual depth equation and also propose a velocity analysis workflow for velocity scanning. The tests to synthetic and field data prove the velocity analysis methods adopted in this paper are robust and valid.  相似文献   

Turbulent intensity and its similarity function over an Inner Mongolian grassland during spring     

YUE Ping      NIU ShengJie  HU YinQiao & ZHANG Qiang Key Laboratory of Arid Climate Change  Reducing Disaster of Gansu Province  Key Laboratory of Arid Climate Change  Reducing Disaster of CMA 《中国科学:地球科学(英文版)》2010,(5)

Macroscopic reason for the development of turbulences in fluid is the conjunction action of velocity and temperature shears. We use the 2008 spring flux observations in the surface layer over Inner Mongolian grassland, obtain the similarity functions of turbulent intensity under different stratification stability conditions, and calculate the clear day turbulent intensity in the spring, which is then analyzed and compared with the observed values of turbulent intensity. The results show that in the Inner Mo...  相似文献   

近距离交叉隧洞爆破对既有隧道的振动影响     

叶培旭  杨新安  凌保林  张业炜 《岩土力学》2011,32(2):537-541

结合南山下隧洞下穿温福客运专线钱仓山隧道工程,实时监测近距离交叉隧洞爆破施工对既有隧道的振动影响。实测结果表明,（1）迎爆面位置影响既有隧道断面的爆破振动速度分布;震源距离测点大于30 m时,距离是爆破振动的主要影响因素;震源距离测点小于30 m时,主要影响因素则为装药量与距离。（2）岩体越坚硬完整,爆破振动波传播衰减越慢。采用导洞先行预留光面爆破、导洞爆破掏槽眼和周边眼及底板眼分开起爆、控制最大段装药量等措施,可有效地降低爆破振动影响,控制其对钱仓山隧道的影响,对类似工程有借鉴作用。  相似文献   

塔里木盆地巴麦地区石炭系低速异常碳酸盐岩的解释     

郭倩  蒲仁海 《吉林大学学报(地球科学版)》2011,41(3):689-696

巴麦地区即塔西南巴楚隆起-麦盖提斜坡,具有台地边缘-斜坡的古构造和古地理背景,这种台地边缘和典型的浅滩沉积暗示了该区具有发育生物礁的环境特征。区内先巴扎（XBZ）600 km²三维地震探区石炭系发育了巴楚组（C₁b）生屑灰岩及标准灰岩、小海子组（C₂x）3套灰岩,其中小海子组发现特殊响应碳酸盐岩,主要表现为厚度增大、频率增高、多出一条波峰同相轴的地震响应特征。通过差异厚度法、底面拉平法、地震属性法、正反演模型法,结合野外露头、岩心、镜下观察、录井、沉积相等综合分析,可初步推测该低速异常体为厚度增加、孔隙度增大的近东西向台地边缘障壁礁所致。礁体东西走向延伸超过25 km,礁核区小海子组灰岩最厚62 m,礁外的小海子组50 m。台缘斜坡南倾,坡度陡,水平宽度1~2 km。礁后生屑滩北倾,坡度缓,水平宽度3~6 km。受色力布亚断裂带遮挡,该生物礁储层可以形成有利圈闭,面积约为42 km²,厚约45 m。  相似文献   

均质土中PCC桩与实心桩动力响应对比分析     

丁选明  刘汉龙 《岩土力学》2011,32(Z1):260-264

现浇混凝土大直径管桩(简称PCC桩)由于具有较大的内、外壁摩阻力,在竖向荷载作用下表现出与一般实心桩不同的静、动力特性。采用建立的解析公式,对PCC桩、等截面积实心桩和等外直径实心桩3种桩的动力响应进行了对比分析,研究结果表明,当桩端阻力相对较小时,3种模型位移幅值差别不大;当桩端阻力较大时,3种模型幅频曲线和相频曲线存在较大差别;等面积实心桩位移幅值比PCC桩稍大,而等外直径实心桩的位移幅值比PCC桩稍小;位移相频曲线呈现等间距的震荡,实心桩的震荡峰值比PCC桩要高,且震荡峰值对应的频率各不相同,PCC桩出现震荡峰值的频率比实心桩小;3种计算模型动刚度震荡幅值差别较大,等直径实心桩的动刚度最大,等面积实心桩次之,PCC桩最小;等直径实心桩的虚部最大,PCC桩次之,等面积实心桩最小,振动过程中等直径实心桩桩顶阻尼最大;等面积实心桩的速度导纳最大,PCC桩次之,等直径实心桩最小。PCC桩充分发挥了单方混凝土的性能,比等截面实心桩具有更小的动力响应,比等外径实心桩更节省混凝土。  相似文献   

岩体波速与坝基岩体变形模量关系   总被引：1，自引：0，他引：1  

宋彦辉  巨广宏  孙苗 《岩土力学》2011,32(5):1507-1512

岩体变形模量是岩体工程设计最重要的参数之一,尽管其可以通过各种现场试验来获得,但因其耗时、费力、投资大,使得许多中小型工程及大型工程的初步设计阶段无法通过试验来得到这一参数。因此,许多研究者建立了诸多岩体变形模量与岩体物理力学参数或岩体质量分级之间的相关关系,如岩体变形模量与RQD、RMR分级、Q分级、岩体纵波速度等之间的关系,从而利用这些关系估算岩体变形模量。总结了已有估算岩体变形模量的各种方法,讨论了其应用条件及预测结果,重点分析了利用岩体纵波速度估算岩体变形模量的方法及存在的问题,并以玛尔挡坝址为实例,建立了相关预测公式。通过与已有估算方法的对比研究,阐明了各种方法预测结果的异同,表明其建立的估算公式与Barton等公式具有较好的一致性,可以用来估算岩体的变形模量  相似文献   

粘性土剪切波速不确定性的统计分析     

刘红帅  郑桐  薄景山  刘德东  齐文浩 《世界地震工程》2010,(Z1)

土体剪切波速具有显著的不确定性。基于全国地震安全性评价工作实测的粘性土的大量剪切波速数据,采用2χ检验方法研究了粘性土不同埋深的剪切波速的概率分布。依据所获得的概率分布,采用相应的统计方法给出了粘性土不同埋深的剪切波速的平均值、最大值、最小值、标准差和变异系数,并给出了95%参考值下限和上限,所获得的结果可用于检验场地剪切波速测试结果的可靠性和粗略估计无实测资料场地土的剪切波速。  相似文献   

Running safety analysis of a train on the Tsing Ma Bridge under turbulent winds     

Weiwei Guo  He Xia  Youlin Xu 《地震工程与工程振动(英文版)》2010,9(3):307-318

The dynamic responses of the Tsing Ma suspension bridge and the running behaviors of trains on the bridge under turbulent wind actions are analyzed by a three-dimensional wind-train-bridge interaction model. This model consists of a spatial finite element bridge model, a train model composed of eight 4-axle identical coaches of 27 degrees-of-freedom, and a turbulent wind model. The fluctuating wind forces, including the buffeting forces and the self-excited forces, act on the bridge only, since the train runs inside the bridge deck. The dynamic responses of the bridge are calculated and some results are compared with data measured from Typhoon York. The runnability of the train passing through the Tsing Ma suspension bridge at different speeds is researched under turbulent winds with different wind velocities. Then, the threshold curve of wind velocity for ensuring the running safety of the train in the bridge deck is proposed, from which the allowable train speed at different wind velocities can be determined. The numerical results show that rail traffic on the Tsing Ma suspension bridge should be closed as the mean wind velocity reaches 30 m/s.  相似文献   

Near‐fault effects on residual displacements of RC structures          下载免费PDF全文

Eftychia Liossatou  Michael N. Fardis 《地震工程与结构动力学》2016,45(9):1391-1409

Residual displacements of single‐degree‐of‐freedom systems due to ground motions with velocity pulses or fling step displacements are presented as a function of period T and of its ratio to the pulse period T_p. Four hysteretic behaviors are considered: bilinear elastoplastic, stiffness‐degrading with cycling, stiffness‐cum‐strength degrading, with or without pinching. When expressed in terms of T/T_p, peak inelastic and residual displacements due to motions with a pulse or fling appear similar to those due to far‐fault motions, if the response to far‐field records are expressed in terms of the ratio of T to the record's characteristic period. However, as the latter is usually much shorter than the pulse period of motions with fling, the range of periods of interest for common structures becomes a short‐period range under fling motions and exhibits very large amplification of residual and peak inelastic displacements. Similar, but less acute, are the effects of motions with a velocity pulse. Wavelets of different complexity are studied as approximations to near‐fault records. Simple two‐parameter wavelets for fling motions overestimate peak inelastic displacements; those for pulse‐type motions overestimate residual displacements. A more complex four‐parameter wavelet for motions with a velocity pulse predicts overall well residual and peak displacements due to either pulse‐ or fling‐type motions; a hard‐to‐identify parameter of the wavelet impacts little computed residual displacements; another significantly affects them and should be carefully estimated from the record. Even this most successful of wavelets overpredicts residual displacements for the periods of engineering interest. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献