二维地基中空沟−波阻板联合隔振屏障分析     

周凤玺  马强  周志雄 《岩土力学》2020,41(12):4087-4092

针对地基隔振控制,提出了一类新型的空沟?波阻板联合隔振屏障,并对其隔振性能进行了数值分析。首先,利用复伸展坐标变换,在频域内建立了完全匹配层（perfect matched layer, PML）吸收边界的控制方程;其次,利用Galerkin近似技术,给出了以位移为基本未知量的二阶非分裂格式PML的频域有限元计算列式;最后,通过数值算例分析了空沟?波阻板联合隔振屏障的物性参数（地基与波阻板的模量比）、几何参数（空沟深度、波阻板深度）以及载荷参数（振动波频率）等对其隔振性能的影响规律。结果表明,空沟?波阻板联合隔振屏障结合了空沟和波阻板各自的优势,可以有效地控制不同频率振源引起的地基振动。  相似文献   

托普台区块高渗透地层随钻堵漏剂配方优化          下载免费PDF全文

田建东  于培志  牟福权 《探矿工程》2015,42(7):10-13

托普台区块上部地层以砂泥岩层、砾质砂岩为主,容易发生漏点不明确、漏失段长的高渗透性漏失。通过对堵漏材料的配伍性评价及合理级配,优选出了一种适合高渗透性漏失地层的随钻堵漏剂。该堵漏剂对钻井液流变性影响小,可降低钻井液API滤失量,对沙床封堵后承压能力＞10 MPa,在TP328X井的应用表明,高强度弹性石墨颗粒复合凝胶堵漏对于高压差、高渗透漏失的工况,可以有效封堵漏层,特别适用于对于漏层不明、漏涌同层、裸眼等复杂井况。  相似文献   

新疆东部卡瓦布拉克地区古生代岩浆活动对中天山地块构造归属的指示意义     

木扎帕尔·木合塔尔  尼加提·阿布都逊  郭瑞清  宫相宽  崔涛  宋志豪 《地质学报》2020,94(5):1450-1461

卡瓦布拉克地区位于中天山地块南缘。该区古生代侵入岩类广泛发育,是探究中天山构造演化及地壳生长历史的重要窗口。本文获得该区两件二长花岗岩样品的LA-ICP-MS锆石U-Pb定年结果分别为447.4±4.9Ma、422.6±5Ma。LA-MC-ICP-MS锆石Hf同位素原位分析结果显示,其εHf(t)值分别为7.1～11.9、5.8～11.8,对应的二阶段模式年龄为674～963 Ma、514～1043 Ma。侵入于晚古生代花岗岩中的中—基性岩脉携带多期捕获锆石,其εHf(t)介于-7.4～4.8,对应的模式年龄变化范围为1.47～2.54Ga。卡瓦布拉克地区古生代花岗岩及中—基性岩脉中捕获锆石所反映的基底信息表明,中天山与塔里木在中元古代(～1.4Ga)、新元古代(～800Ma)以及古生代(～400Ma)期间岩浆活动具有截然不同的源区特征。结合前人研究成果,认为中天山与塔里木不具有构造亲缘性。  相似文献   

碰撞造山带超高温变质作用及构造意义——以泛非造山带为例     

滕霞  张建新 《岩石学报》2020,36(10):2963-2982

超高温（≥900℃）变质作用发生在自太古代以来的各个地质历史时期,目前极可能也正发生在青藏高原地壳深部。同时,它也是以冈瓦纳为代表的超大陆在最终拼合时的显著标识,这一关联指示了超高温变质作用与碰撞造山带的密切关系。本文总结了东冈瓦纳内与泛非造山作用有关的典型超高温变质岩的分布、岩石学特征、峰期变质条件、P-T轨迹及形成时代,并简要介绍我们在柴达木地块西段新识别出的泛非期超高温变质作用的基本特征。结合东冈瓦纳超高温变质作用特征和造山带热模拟研究的新进展,本文获得以东冈瓦纳超高温变质作用为代表的碰撞造山带超高温变质作用的几点认识：1）东冈瓦纳麻粒岩地块中的超高温变质岩和普通麻粒岩记录了相似的变质年龄、P-T轨迹以及呈过渡变化的峰期温度,两者可能是同一构造事件的产物,共同组成一个高温-超高温变质岩单元;2）超高温变质作用在东冈瓦纳内部持续了至少超过30Myr,但未见呈大规模的同期或近同期基性岩岩浆出露,指示此处需要的长期热源不是地幔来源岩浆;3）虽然数值模拟能成功呈现加厚地壳被放射元素衰变热加热至超高温条件的情况,且加热及持续时间与东冈瓦纳超高温变质约束的结果相当,但是模拟中需要的高生热值暗示,在自然界中,完全只靠放射性元素衰变生热或许不能让碰撞造山带内达到超高温条件;4）碰撞造山带经历了长期的构造演化,这一过程中,造山带内地壳不太可能同时达到超高温变质条件,这一特征可能反映在P-T-t轨迹的差异上,对这些轨迹的系统研究有助于对超高温变质作用的构造-热过程的理解。  相似文献   

塔里木盆地顺北区块二叠系井漏复杂的分析及对策          下载免费PDF全文

董小虎  李银婷 《探矿工程》2020,47(2):59-62

顺北区块钻井项目施工中,二叠系的井漏复杂情况较多,漏失量大,易发生再次或多次漏失,严重时导致井壁垮塌掉块卡钻,致使井下复杂情况高发,给钻井工程带来损失,影响了该区块的勘探开发速度。二叠系火成岩发育,地层裂缝发育,地层破裂,钻井时井下复杂主要表现为漏失。针对此问题开展了顺北地区二叠系井漏复杂分析,结合顺北区块施工项目的实际情况以及二叠系地层特点,分析了该区块的二叠系钻进难点,总结了随钻堵漏技术具体的施工措施和不同漏速下的堵漏方案.经过实践验证,该综合防漏堵漏对策能有效减少井漏复杂,提高堵漏效率。  相似文献   

腾冲地块稀土地球化学背景与泥岩中稀土超常富集特征     

刘东盛  周建  严桃桃  迟清华  徐善法  王玮  韩志轩  李瑞红  王强  王学求 《地球学报》2020,41(6):759-769

近年来围绕腾冲地块花岗岩取得了一系列重要稀土勘查突破, 深入了解稀土元素地球化学背景是稀土矿产勘查的基础。系统总结腾冲地块全国地球化学基准值和区域化探扫面获得的水系沉积物和 9个主要地质单元岩石的稀土元素分布, 查明区域稀土元素地球化学背景。稀土元素主要在新近系泥岩、白垩纪花岗岩和全新世火山岩, 其中新近系芒棒组泥岩具有稀土超常富集, 稀土平均含量达444×10–6, 是地壳克拉克值的3倍, 并与水系沉积物La地球化学异常具有空间对应关系, 结合区域地质成矿条件和新类型稀土矿成矿特点, 认为除白垩纪花岗岩以外, 腾冲地块芒棒组泥岩和全新世火山岩可能具有形成稀土矿的潜力  相似文献   

Marginal accretion processes of Jiamusi Block in NE China: Evidences from detrital zircon U-Pb age and deformation of the Wandashan Terrane     

《Gondwana Research》2020

The eastern segment of Central Asian Orogenic Belt underwent not only a long evolution history related to the Paleo-Asian Ocean during Paleozoic but also the tectonic overprinting by the westward subduction of Paleo-Pacific Ocean crust during Mesozoic. When the subduction of Paleo-Pacific Ocean crust started has been long debated issue for understanding the tectonic evolution of the eastern Asian continental margin. The eastern margin of the Jimusi Block (Wandashan Terrane) preserved complete records for the accretionary process of the westward subduction of Paleo-Pacific Ocean crust. Comprising the Yuejinshan Complex and Raohe Accretionary Complex (RAC), the Wandashan Terrane is located in the eastern margin of Jiamusi Block, NE China, and is considered to be an accretionary wedge of the westward subducting oceanic crust. To reconstruct the marginal accretion processes of the Jiamusi Block, the structural deformation of the Wandashan Terrane was investigated in the field and the geochronology of the Dalingqiao and Yongfuqiao formations were studied, which were formed syn-and-post RAC accretion respectively. The Yuejinshan and Raohe complexes were discontinuously accreted to the eastern margin of the Jiamusi Block. Contrary to the previous consideration of the Late Triassic to Early Jurassic, this study suggests that the Yuejianshan Complex in southwest Wandashan Terrane probably accreted from Late Carboniferous to Middle Permian, which was driven by unknown oceanic crust subduction existing to the east (present position) of the Jiamusi Block at that time. The siltstones of the Dalingqiao Fm. yield the youngest zircon U-Pb age of 142 ± 2 Ma, indicating the emplacement of the RAC not earlier than the Late Jurassic. Thus, the RAC might start to accrete from the Jurassic and emplace during 142–131 Ma, resulted from the Paleo-Pacific subduction which started from the Late Triassic to Early Jurassic.  相似文献   

川滇菱形块体各边界垂直形变速率与断层活动特性     

苏琴 《四川地震》2005,(1):43-46,38

依据川滇菱形块体各边界带上所有跨断层垂直形变测量资料,计算各断裂带垂直形变速率合成值,分析各断裂带形变速率特征。结果表明,川滇菱形块体断层活动有南强北弱,西强东弱的特点,该块体东北边界断层活动北段是以压性为主的逆断层,南段是以张性为主的正断层,西南边界断层活动北段以压性为主,南段则以张性为主。  相似文献   

THE FINE CRUSTAL STRUCTURE OF THE SOUTHERN MARGIN OF NORTH CHINA BLOCK REVEALED BY DEEP SEISMIC REFLECTION PROFILE          下载免费PDF全文

FENG Shao-ying  LIU Bao-jin  LI Qian  YUAN Hong-ke  ZHU Guo-jun  TIAN Yi-ming  WANG Hong-wei  HOU Li-hua  DENG Xiao-juan  TAN Ya-li 《地震地质》1979,42(3):581-594

The study area is located at the junction of the northern margin of the Qinling orogenic belt and the southern margin of the North China Block. In order to study the fine crustal structure and the deep-shallow structural features of faults in this area, we conducted deep seismic reflection profiling with the seismic profile of 100km long, directing NE-SW in Zhumadian City, Henan Province, and got clear lithospheric structure images along the profile. As regards the data acquisition, we applied the geometry of 25m group interval, 1000 recording channels and more than 60 folds. Seismic wave exploding applies the 30kg shots of dynamite source with the borehole depth of 25m. The shot interval is 200m. In data processing, we focused on improving the signal-to-noise ratio. Data processing methods mainly include first break removal, tomographic static correction, abnormal amplitude elimination, amplitude compensation, pre-stack denoising, surface consistent deconvolution, velocity analysis, several iterations of the residual static correction, dip moveout, post-stack time migration and post-stack denoising, etc. The profile with high signal-to-noise ratio was obtained. The reflection wave group characteristics is obvious in the crust, which reflects abundant information about geological structure. Along the profile, the crust is characterized by double-layer reflection structure, and the Moho surface is composed of a series of laminated arc-shaped strong reflections. The thickness of the upper crust is about 14.8~20.7km, and the total thickness of the crust is about 32.0~35.1km. The upper crust is dominated by the inclined, densely stratified or arc-shaped reflections. The lower crust is dominated by arc-shaped and inclined reflection, and there is a reflective transparent zone under the Moho surface. The reflection sequences with different directions and shapes in the upper crust constitute the nappe structure in southwest segment and the structural model of two concaves with one uplift in NE segment, which correspond to the north Qinling nappe, Zhumadian-Huaibin depression, Pingyu-Xiping uplift and a secondary depression, respectively. There are abundant arc-shaped reflection sequences in the lower crust, which may represent multi-stage magmatic activities. The deep seismic reflection profile shows that faults in the upper crust are well developed. According to the characteristics of reflected wave field in the profile, four groups of fault structure which contain ten faults with different scales are interpreted. Among them, faults F_P1, F_P2 and F_P3 constitute the thrust fault system in the northern margin of Qinling Mountains, and F_P5 and F_P7 are boundary faults of Zhumadian-Huaibin depression. These faults are all developed within the upper crust. In addition, the Fault F_PM is a large fault that cuts through the lower crust and Moho surface. The deep seismic reflection profile reveals the crustal structure and deep-shallow structural features of faults at the junction of the northern margin of the Qinling orogenic belt and the southern margin of the North China block, which provides seismological evidence for the analysis of structural differences, the deep earth's interior processes and deep-shallow structural relationships between the Qinling-Dabie orogenic belt and the southern margin of the North China block. The lower crust of the study area is divided into two parts by deep faults that dislocate the Moho surface. These two parts have distinct reflective structures, suggesting that the area has experienced intense complex tectonic movements. The faults in the upper crust control the formation of basin-mountain structure and stratigraphic deposition of this area. And deep faults in the crust that disrupt Moho surface create conditions for the upwelling and energy exchange of deep materials. All of these have regulated the composition of material and the distribution of energy in the crust. The deep faults cutting through the lower crust and Moho surface and the south-dipping arc-shaped and inclined strong reflection sequences developed in the lower crust should indicate the large-scale subduction of the southern margin of the North China block towards the south-trending Qinling orogenic belt.  相似文献   

疏浚中基于Matlab的土方量计算方法     

张翠峰  万计 《地理空间信息》2010,8(5):138-140

通过比较疏浚测量中计算土方量所采用的平均水深方法和不规则三角网法,结合工程实例,提出了一种基于插值运算的软件算法,并对三者进行了对比分析,得出程序算法在疏浚测量计算土方量工作中的特点和优势。  相似文献