Experimental investigation on scour topography around high-rise structure foundations   总被引：1，自引：0，他引：1  

Yang Xiao  Hao Jia  Dawei Guan  Dongfang Liang  Saiyu Yuan  Hongwu Tang 《国际泥沙研究》2021,36(3):348-361

The current study aims to investigate the characteristics of scour topography around High-Rise Structure Foundations(HRSFs)via physical modeling tests.Clear-water scour tests with a uniform non-cohesive bed are modeled under the action of unidirectional steady flows.Time variations of the erosion and deposition topography are measured.The results show that deposition downstream of the first dune behind the HRSF is not located on the centerline of the wake.The deposition pattern indicates that a long steady wake region exists behind the permeable foundation.The scour depth around an HRSF is much less than that around a monopile because of the structural permeability,which gives rise to the bleed flow and a weakened downflow and horseshoe vortex.Additionally,the asymmetry of the HRSF affects the scour rate but not the final equilibrium scour depth.The average scour slope decreases along the direction of the flow.On the contrary,the scour radial distance increases along the direction of the flow,with the average value changing from 1.36De to 2.35De(where De is the equivalent diameter of the foundation).Furthermore,the scour hole around the HRSF is serrated rather than smooth owing to the presence of multiple piles.Empirical formulae are suggested for estimating the evolution of scour depth and volume.These laboratory experiments provide reference information for relevant numerical modeling studies and can be applied to guide engineering designs in an ocean area.  相似文献   

Crustal Structure of the Chuan-Dian Block Revealed by Deep Seismic Sounding and its Implications for the Outward Expansion of the East Tibetan Plateau     

XIONG Xiaosong  WANG Guan  LI Qiusheng  LU Zhanwu  GAO Rui  FENG Shaoying  WU Guowei 《《地质学报》英文版》2022,96(6):1932-1944

The Chuan-Dian Block (CDB) is located in the southeastern margin of the Tibetan Plateau, with a complex geological structure and active regional faults. The present tectonic condition with strong crustal deformation is closely related to the ongoing collision of the India and Eurasia plates since 65 Ma. The study of the crustal structure of this area is key to revealing the evolution and deep geodynamics of the lateral collision zone of the Tibetan Plateau. Deep seismic sounding is the most efficient method with which to unravel the velocity structure of the whole crust. Since the 1980s, 19 deep seismic sounding profiles have been captured within the CDB area. In this study, we systematically integrate the research results of the 19 profiles in this area, then image the 3D crustal velocity, by sampling with a 5 km spacing and 2D/3D Kriging interpolation. The results show the following. (1) The Moho depth in the study area deepens from 30 km in the south to 66 km in the north, whereas there is no apparent variation from west to east. The Pn wave velocity is higher in stable tectonic units, such as 7.95 km/s in the Lanping-Simao block and 7.94 km/s in the western margin of the Yangtze block, than in active or mobile tectonic units, such as 7.81 km/s in the Baoshan block, 7.72 km/s in the Tengchong block and 7.82 km/s in the Zhongdian block. (2) The crustal nature of the Tengchong block, the northern Lanping-Simao block and the Zhongdian block reflects a type of orogenic belt, having relatively strong tectonic activities, whereas the crustal nature of the central Lanping-Simao block and the western margin of the Yangtze block represents a type of platform. The different features of the upper-middle crust velocity, Moho depth and Pn wave velocity to both sides of the Red River fault zone and the Xianshuihe fault zone, reflect that they are clearly ultra-crustal. (3) Based on the distribution of the low velocity zones in the crust, the crustal material of the Tibetan Plateau is flowing in a NW–SE direction to the north of 26°N and to the west of 101°E, then diverting to flowing eastwards to the east of 101°E.  相似文献   

联合脱氮法用于硝酸盐污染地下水修复的机理研究   总被引：1，自引：0，他引：1  

黄国鑫  高云鹤  Howard Fallowfiel  Huade Guan  刘菲 《岩矿测试》2012,31(5):855-862

地下水硝酸盐已经成为了世界性环境和健康问题。目前针对硝酸盐的化学还原脱氮、自养脱氮、异养脱氮等单一脱氮方法研究较多;联合脱氮体系包括化学还原、自养脱氮和异养脱氮三种脱氮途径,综合了单一脱氮法的优点,但研究甚少。本研究通过静态批试验,采用零价铁、甲醇和混合菌液研究了联合脱氮法的脱氮能力、脱氮产物、脱氮途径及脱氮机理。结果表明,5 d后单一的零价铁化学还原、自养脱氮和异养脱氮的去除率分别为5.79%、14.30%和63.03%;而联合脱氮的去除率接近100%,去除效果显著优于单一的化学还原脱氮、自养脱氮或异养脱氮。在联合脱氮法体系中,零价铁化学还原、自养脱氮未引起亚硝酸盐积累,而异养脱氮造成了亚硝酸盐积累;化学还原、自养脱氮和异养脱氮引起的铵盐增量均<0.6 mg/L,绝大部分硝酸盐未被还原成铵盐,进而省去了后续除铵工艺;零价铁化学还原、自养脱氮、异氧脱氮三者发生协同作用,表现于在厌氧环境下,零价铁发生腐蚀,产生阴极氢和二价铁,为自养脱氮菌提供了电子供体,从而促进了自养脱氮;异养脱氮不仅占主导地位,而且还会产生CO2,CO2被自养脱氮菌作为无机碳源加以利用,从而提高了体系中自养脱氮能力。这种协同作用表现为联合脱氮法的去除率增加,而在单一的异养脱氮或自养脱氮体系中则无法形成这一良性过程。实验表明联合脱氮法是一种潜在的有效可行的地下水原位修复方法。  相似文献   

Advances in interscale and interdisciplinary approaches to the South China Sea     

Lingling Xie  Yi Guan  Jianyu Hu  Quanan Zheng 《海洋学报(英文版)》2021,40(11):196-199

The South China Sea (SCS) connects the Pacific Ocean and the Indian Ocean, and acts as an important part in regional and global climate systems (e.g., Qu et al., 2009; Wang et al., 2009). Multi-scale dynamic and biogeochemical processes in the SCS, comprising a hot spot in marginal sea studies, have attracted great attentions from researchers (e.g., Chen et al., 2020; Hu et al., 2020). The South China Sea Annual Meeting (SCSAM) 2021, recently held on October 22–24 in Zhanjiang, China, focused on academic exchanges of the newly research results and progresses in the interdisciplinary multi-scale processes in the SCS. The SCSAM 2021 is the eighth international workshop of the series, which started in April 2013 (Zhu, 2013) and renamed as SCSAM in 2018. There were 90 oral presentations and 57 posters in the meeting this year, which attracted attentions of more than 2000 audiences both on line and on site. This short article summaries the cutting-edge advances in interscale and interdisciplinary approaches to the SCS from the meeting presentations and the associated research.  相似文献   

Analysis on mechanisms of anomalous variations of tropopause pressure over the Tibetan Plateau during summer in Northern Hemisphere     

BaoLin Zhu  ChuHan Lu  ZhaoYong Guan  Zhi Cheng  WenJun Liu 《寒旱区科学》2012,4(2):0154-0162

Using the monthly mean data from NCEP–NCAR reanalysis, through building tropopause pressure index, we investigated the mechanisms of anomalous variations of tropopause pressure over the Tibetan Plateau during summer in Northern Hemisphere. For comparative analysis we selected representative years of 1992 and 1998 to study, and they were respectively the highest and the lowest year of tropopause pressure anomaly over the Tibetan Plateau. The results are summarized as follows: (1) Over the Tibetan Plateau, the variations of tropopause pressure are well correlated respectively with anomalous temperature and geopotential height in both troposphere and stratosphere. Besides, the anomalous tropopause pressure has also close relation with anomalous surface temperature in the Tibetan Plateau. In 1992, the surface temperature was anomalously low, correspondingly, the tropopause pressure over the Tibetan Plateau was anomalously high; but in 1998, the opposite was the case. (2) Over the Tibetan Plateau, the correlation of tropopause pressure and OLR (Outgoing Longwave Radiation) is found to be positive. Furthermore, by further diagnosing the circulation fields between 850 hPa and 200 hPa levels and the whole troposphere vapour field, we found out that the anomalously high tropopause pressure in 1992 corresponded to the anticyclonic divergence of low level wind fields and the cyclonic convergence of high level wind fields, and coupled with divergence of the whole troposphere vapour fields along with the South Asian High weakened at the same time. While in 1998, the case was opposite to that in 1992. These facts indicated that the anomalous convection resulted in the significant difference of tropopause pressure in 1992 and 1998 over the Tibetan Plateau. (3) The vertically integrated heat budget anomalies were responsible for explaining tropopause pressure anomalies in 1992 and 1998 over the Tibetan Plateau.  相似文献   

COMPARISON OF HEAVY METAL CONCENTRATIONS IN SURFACE SEDIMENT OF TANJUNG PIAI WETLAND WITH OTHER SITES RECEIVING ANTHROPOGENIC INPUTS ALONG THE SOUTHWESTERN COAST OF PENINSULAR MALAYSIA     

Chee Kong Yap Mew Seong Choh Franklin Edward Berandah Ahmad Ismail Soon Guan Tan 《湿地科学》2006,4(1):48-57

1 INTRODUCTIONOur sampling trip to Tanjung Piai wetland in2002 showed that the site had not been developed andrecognized yet as a wetland of international importance(Ramsar). Recently, our field trip in January 2005to the same site to collect sediment sam…  相似文献   

共中心点迭加资料的Born反演和偏移间的关系     

Guan Cheng  Shimon Coen  杨有发 《世界地质》1986,(2)

引言偏移,在地震勘探资料数字处理中显得越来越重要,应用越来越广泛。这是因为,无论过去和现在,准确地确定地下地质体的位置、形态及有关物性参数,始终是地震勘探的宗旨。而偏移——对地震资料反演或地震剖面成像是很重要的处理方法。  相似文献   

Seismological Research on the Mining Tremors     

Zhang Shaoquan  Guan JieInsntute of Geophysics  SSB  Beijing  China Beijing Mining Bureau  Beijing  China 《中国地震研究》1995,(1)

A sophisticated seismological method has been introduced to the study of mining tremors by the Institute of Geophysics,SSB in cooperation with the Beijing Mining Bureau of NCC.Achievements have been obtained in the following areas:modification of the seismic monitoring system,compilation of a software package for analysis of mining tremors,research on the mechanical model for mining tremors,classification of mining tremors and development of an expert system of tremor prediction.  相似文献   

Isotope Effect of Precipitation and Motion Regularity of Rainfall Cloud in the South Tibet     

Yin Guan  Wang Jun  Liu Tianchou WT  ”BX 《地学前缘》2000,(Z1)

ISOTOPE EFFECT OF PRECIPITATION AND MOTION REGULARITY OF RAINFALL CLOUD IN THE SOUTH TIBET  相似文献   

Research on the coordinated utilization of land resource in the intergrated economic region of industry, farming and grazing-a case study of Baotou city in Inner Mongolia     

Wu Xianhui  Guan Zhuojin  YANG Yu-mei 《地理学报(英文版)》2000,(4)

Land resources constitute the basic resource for national economic development, and it is the environment of all economic activities. Lacking land resource, any economic activities can not process. And, for Baotou City, a new industrial city developed in farming-grazing transitional zone, the land resource is even more important for economic development. Industry, farming and grazing all demand much land resource, and the land resource is the main dependence of their symbiotic development. So…  相似文献