大型桥梁冲刷防护工程损坏特性研究   总被引：2，自引：0，他引：2  

高正荣  杨程生  唐晓春  俞竹青 《海洋工程》2016,34(2):24-34

以苏通大桥为例,通过模型试验和冲刷防护工程及周边河床地形的长期监测开展了大型桥梁冲刷防护工程的损坏特性研究。研究结果表明,大型桥梁冲刷防护工程存在两种损坏形式:防护工程防护区面层冲刷损坏和防护工程护坦边坡坍塌损坏;防护工程的破坏主要发生在防护工程后1~2年内。提出了以"损坏率"和"稳定边坡"分别表示两种不同类型的破坏指标。同时,提出了防护工程"成型稳定工程量基准线"概念,为监测冲刷防护工程稳定性制定定量目标。研究结果还表明,在防护体稳定后,防护区呈"洪季淤积、枯季冲刷"特点,这一变化对防护体稳定影响有限。研究结果为类似工程设计、监测、维护和相关研究提供参考。  相似文献   

Holocene palaeoflood events recorded by slackwater deposits along the middle Beiluohe River valley,middle Yellow River basin,China          下载免费PDF全文

Yuzhu Zhang  Chun Chang Huang  Jiangli Pang  Xiaochun Zha  Yali Zhou  Xiaqing Wang 《Boreas: An International Journal of Quaternary Research》2015,44(1):127-138

Palaeohydrological investigations were carried out in the middle Beiluohe River valley in the middle Yellow River basin. Palaeoflood slackwater deposits (SWDs) are natural records of overbank flooding and are often identified in the Holocene aeolian loess–soil profiles along the river valley. Three bedsets of palaeoflood SWDs were found within the mid‐Holocene Climatic Optimum palaeosol (S₀) on the right riverbank. Both the sedimentary and the analytical results, including magnetic susceptibility, grain‐size distribution and concentrations of chemical elements, indicate that these palaeoflood SWDs were deposited from the suspended sediment load of overbank flooding. We identified three episodes of extraordinary overbank flooding events. These hydro‐climatic events were dated to 7600–7400, 5800–5000 and 4200–4000 a BP, from optically stimulated luminescence (OSL) dating and pedostratigraphical correlation. The minimum flood peak discharges were estimated to have been between 12 600 and 14 100 m³ s^?1 using the slope–area method. These hydro‐climatic events are considered to be a regional expression of known climatic events and demonstrate that the mid‐Holocene climate was far from stable. These results show that the magnitudes of floods are highly sensitive to climate change in semi‐arid and sub‐humid regions with a monsoonal climate.  相似文献   

黄上丘陵林地土壤侵蚀与土壤性质变化     

查小春  唐克丽 《地理学报(英文版)》2003,13(3):373-378

The serious soil erosion caused the fragile eco-environment in the Loess Plateau. In modern soil erosion of the Loess Plateau, the man-made accelerated erosion was the dominant erosion pattern (Tang etal., 1993a; 1993b). There are many kinds of human activities to accelerate erosion, of which the most influential activities are to destroy forest and grass, even to destroy vegetation. Reclamation at the expense of destruction of forestland and grassland artificially could increase soil erosio…  相似文献   

Hydraulic Fracture Initiation and Propagation from Wellbore with Oriented Perforation     

Haiyan Zhu  Jingen Deng  Xiaochun Jin  Lianbo Hu  Bo Luo 《Rock Mechanics and Rock Engineering》2015,48(2):585-601

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Lead tolerance and accumulation in three cultivars of Eucalyptus urophyllaXE.grandis: implication for phytoremediation     

Xiaochun Peng  Bing Yang  Dongmei Deng  Jiahua Dong  Zhiliang Chen 《Environmental Earth Sciences》2012,67(5):1515-1520

Eucalyptus urophyllaXE.grandis is a fast-growing economic tree species that contributes to habitat restoration of degraded or fragile environments. Hydrophonic experiments were performed to evaluate the extent of lead (Pb) tolerance and accumulation in three cultivars of this species, ST-2, ST-9 and ST-29, when exposed to nutrient solutions with different concentrations of Pb [7, 14, 28 or 56 mg Pb L^?1 as Pb(NO₃)₂]. Obtained results showed that, in the presence of Pb treatments, ST-9 grows well without any toxicity symptoms of leaf necrosis and reduced growth, indicating its feature of tolerance to Pb. Furthermore, marked variation in Pb accumulation was found among plant organs (roots, shoots and leaves), cultivars and Pb supply. In most cases, cultivar ST-9 was shown to accumulate more Pb than others. In conclusion, E. urophyllaXE.grandis ST-9 can be a good choice for remediating Pb-contaminated soils.  相似文献   

基于SDCORS的车载RTK高程注记点连续采集精度分析     

凌晓春  刘石栋  刘振军  汤玉兵 《山东地质》2014,(5):68-71

为提高航测法数字线划图（DLG）的生产效率,尽可能减少外业作业时间,基于山东省卫星定位连续运行综合服务系统（SDCORS）的车载RTK技术进行高程注记点采集。采用不同时间（白天、晚上）、不同车速条件进行高程注记点连续采集,并与常规方法（全站仪、单基站RTK）采集高程点进行比较,求取高程中误差,认为在夜间以不大于20 km/h的车速进行采集精度较高。在数字海阳基础地理信息数据采集项目中,利用车载RTK采集346 km2范围内的沿路高程注记点,结果表明能够满足1∶500航测法成图精度要求。  相似文献   

二氧化碳捕获与封存的主要技术环节与问题分析     

张鸿翔  李小春  魏宁 《地球科学进展》2010,25(3):335-340

减少CO2的排放是国际社会当前迫切需要解决的问题,CO2捕获与地质封存技术由于其巨大的减排潜力和经济性近年来引起科学界和政治界的广泛关注。对该技术的主要技术环节和问题进行了分析,并对中国背景下的CO2捕获与地质封存技术的主要问题进行了探讨。  相似文献   

从北华北盆地的地质结构看1976年唐山地震的发震机理     

杨克绳  胡平  党晓春 《地学前缘》2010,17(5):263

北华北盆地经过古近纪拉张、新近纪挤压形成了怀柔—三河—唐山—锦州—下辽河向南突出的弧形构造带,它与向南推挤的南北向唐山—丰南隆起一起构成燕辽山字型构造。唐山—丰南脊柱向南推挤造成弧顶挤压应力集中。一旦应力集中超过极限值,应力必然释放,形成大地震。文章从这一认识出发对1976年唐山地震的发震机理进行了探讨。  相似文献   

黄河中游晋陕峡谷段全新世晚期洪水滞流沉积研究   总被引：2，自引：0，他引：2  

魏海燕  黄春长  査小春  庞奖励  王夏青 《地质论评》2010,56(5):745-752

通过对黄河晋陕峡谷的深入调查研究,在延长永和县河段发现了典型的全新世晚期洪水滞流沉积剖面。在野外考察中,对沉积物的宏观特征和沉积环境及其分布特征进行观察,并进行了系统采样。在实验室对沉积物样品进行了粒度成分、磁化率、烧失量、CaCO3含量等测定。通过综合分析论证,表明黄河中游晋陕峡谷全新世晚期洪水滞流沉积物以粉砂为主,细砂含量次之,粘粒含量很少,分选性好,磁化率很低。其沉积学分类为细砂质粉砂,是黄河洪水悬移质泥沙在高水位滞流环境下的沉积物。将其与典型的全新世风成黄土和古土壤进行对比,可知其粒度成分比黄土和古土壤更粗,粒级分布更为集中。此外,将其与延河郭家川全新世洪水滞流沉积物对比,发现其粒度频率分布基本相似。该研究结果对于揭示黄河中游洪水水文泥沙特性及其历史演变具有重要意义。  相似文献   

马莲河全新世古洪水沉积学和水文学研究   总被引：3，自引：2，他引：1  

周芳  查小春  黄春长  王夏青  桑京京 《地理科学进展》2011,30(9):1081-1087

通过对马莲河中下游的深入考察,在甘肃省合水县河段发现全新世古洪水滞流沉积剖面,对采集的沉积物样品进行粒度成分、石英砂表面结构等分析,证明为典型的古洪水滞流沉积物。通过地层学年代对比分析,确定马莲河在全新世中晚期发生特大洪水,年代大致为4200-4000a B．R之间。根据该组古洪水滞流沉积物所指示的洪峰水位,采用比降法恢复洪峰流量在16400～16900m^3／s之间。同时对该断面2003年和2005年洪水的洪痕进行了流量恢复计算,计算结果与实测洪水误差小于5％,证明古洪水水文学计算结果合理可靠,从而为马莲河水利工程建设及沿岸城镇的防洪减灾提供了科学依据。  相似文献