气井水力压裂有效缝长评估及影响因素研究     

肖晖  郭建春  任山 《现代地质》2013,27(6):1434

为了准确确定气井压后有效缝长及其影响因素,提高川西须家河气藏水力压裂针对性,对于具备生产历史拟合条件的气井,利用数值模拟软件进行了生产历史拟合获得有效水力裂缝缝长,与采用净压力拟合方法获得的水力裂缝支撑缝长进行对比和拟合,获得了有效缝长和支撑缝长的关系式,计算了川西须家河储层单井压后有效缝长;采用灰色关联分析理论分析了各个参数对有效缝长的影响程度和对压裂设计的启示。结果表明：压后有效缝长与支撑缝长具有较强相关性(Le=00584 Lp1359 3),有效缝长明显比支撑缝长短;施工参数(特别是用液量)是影响须家河储层有效缝长的关键,而储层和隔层间应力差则是影响有效缝长的重要客观因素。该研究方法为水力压裂压后评估和提高压裂设计水平提供了较好的借鉴。  相似文献   

南北地震带强震主体活动区现象及未来趋势分析     

姚玉霞  王建荣  马凤珍  马海霞 《地震地磁观测与研究》2012,33(3):37-40

通过分析我国南北地震带（以下简称南北带）有仪器记录以来发生的大震后,发现存在约10年主体大震活动区,并自北而南有4次转移图像;同时对汶川8级大震前后的震情活动进行分析,认为未来10年南北带北段及以西地区将进入活跃期,很有可能发生多次7级以上地震,但也可能南移;未来几年四川地区可能再次发生大震,甘肃东南部地区有可能发生6级以上地震。  相似文献   

基于球形固结模型的桩端后注浆残余应力理论研究   总被引：1，自引：0，他引：1  

张忠苗  何景愈  房凯 《岩土力学》2012,33(9):2671-2676

基于球形空腔扩张及一维径向固结理论,对桩端后注浆桩的桩端注浆残余应力进行理论研究,分析了残余应力的消散过程,在负指数衰减的初始超孔隙压力分布基础上,得到了残余应力随时间及扩散半径消散的解析解;同时将提出的方法与未考虑浆液扩散半径影响的简化方法进行了比较,对模型的主要影响参数进行了分析。参数分析显示,流变指数、稠度系数、土体的压缩模量及固结时间是影响注浆残余应力的关键因素;另外,通过试验实测数据对新方法及简化计算方法进行了验证,结果表明,新计算方法能有效地模拟后注浆残余应力的消散。其研究结果对后注浆残余应力的理论研究及工程实践有重要的指导价值。  相似文献   

Confirming geomorphological interpretations based on portable OSL reader data          下载免费PDF全文

Eric W. Portenga  Paul Bishop 《地球表面变化过程与地形》2016,41(3):427-432

Portable optically stimulated luminescence (OSL) readers are increasingly being used in geomorphological and archaeological investigations, but information regarding data reproducibility and the reliability of interpretations based on portable OSL reader data has not yet been presented to the wider geomorphological community. This Letter addresses these two issues by returning to Grabben Gullen Creek in the southeastern Australian Tablelands where we remeasure a sediment profile that was first measured by other researchers 3 years earlier. We also compare portable OSL reader data measured on sediment interpreted to have been deposited in swampy meadow wetlands and flood alluvium settings with data measured on known swampy meadow and flood deposits. Our data show that portable OSL reader data are reproducible. Moreover, we confirm the earlier interpretation that stratigraphies commonly exposed in southeastern Australian Tablelands valley bottoms reflect pre‐European swampy meadow wetlands and flood alluvium. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

桩端后注浆对大直径灌注桩影响的现场对比试验研究     

李永辉  朱翔  周同和 《岩土力学》2016,37(Z2):388-396

基于郑州三环快速路工程开展的6个场地19根大直径灌注桩现场足尺试验,通过对比分析后注浆桩与未注浆桩实测结果,研究桩端后注浆对大直径灌注桩承载变形性状、荷载传递规律、桩端承载特性及桩侧摩阻力发挥性状的影响。结果表明,桩端后注浆条件下大直径灌注桩承载变形性能明显提高,且提高幅度受注浆龄期影响较为显著;在黄河中下游以中密～密实粉土、粉细砂及可塑～硬塑粉质黏土为主要冲积地层中桩长40 m左右的大直径灌注桩表现为摩擦型桩,但相比于未注浆桩,桩端后注浆桩传递至桩身下部及桩端的荷载更小;桩端后注浆在桩端下形成水泥沉渣坚硬固结体,有效地处理了桩端沉渣问题,且通过渗透劈裂作用,形成深度可达1 m的网状分布的水泥胶结体,加之对桩端土层的压密效应,显著提高了桩端支承性能与承载刚度;桩端后注浆显著提高大直径灌注桩桩侧极限摩阻力发挥水平,并降低了桩侧极限摩阻力对应的桩土相对位移,使得大直径灌注桩在较小的沉降下表现出较高的承载能力。  相似文献   

后压浆技术在央视新台址主楼基础桩中的应用     

芦清建  陈昌富  马永琪 《岩土工程技术》2009,23(4):214-216,F0003

灌注桩后压浆技术以其施工简便,承载力提高幅度大的特点,得到普遍应用。通过实际项目,对灌注桩不同桩长后注浆的现场试验研究,分析其承载变形特性,并在工程实践应用中得到成功。  相似文献   

国产高分系列卫星在森林火灾应急处置中的全流程应用——以四川九龙县三岩龙乡“4·08”森林火灾为例     

唐尧  王立娟  胡光中  赵娟 《中国地质调查》2022,9(5):31-39

四川西部高山峡谷地貌发育,山高林密且地质环境恶劣,区内林草资源丰富,森林火灾多发、易发、频发,灾害应急处置难度大,防控任务重。国产高分系列卫星影像具有时空分辨率高、载荷类型多、机动性强、幅宽范围大、成像迅速等优点,对川西地区森林防灭火、灾害应急处置及防灾减灾等有明显优势。以2021年四川九龙县三岩龙乡“4·08”森林火灾为例,利用国产高分系列卫星数据分别对森林火灾初期、中期及晚期开展应急处置,包括快速解译林火火灾救援要素(初期)、感知亮温异常态势(中期)、跟踪监测过火区动态(中期)、结合火场需求提供应急扑救部署建议(中期)、开展灾损解译评估(晚期)及火后泥石流易发性评价(火后)等,结果表明国产高分系列卫星对森林火灾应急处置的全流程应用具有实践指导意义。  相似文献   

Middle–Late Holocene Paleoclimate and Weathering History in the Norra Storfjället Mountains,Sweden: Deglacial Record and Soil Stratigraphy Applied to Neoglaciation in Lower Latitudes     

William C. Mahaney  Volli Kalm 《Geografiska Annaler: Series A, Physical Geography》2013,95(2):145-158

The retreat record of the Stabre Glacier into the Norra Storfjället mountains, after separation from the massive Tärnaån Glacier at some undetermined time in the Atlantic Chron, is documented by recessional moraines in the foreland. While poorly constrained by radiometric dating, the age of the middle group of moraines averages out to less than 4000 cal ¹⁴C yr BP, the older moraine group probably of Late Atlantic age, with the youngest deposits of Little Ice Age (LIA). Soils/paleosols range from Entisols (youngest) and Inceptisols (middle group) to mature Spodosols (outer group), existing either as single‐story profiles or within pedostratigraphic columns, buried pedons either surfaced with weathered glacial or mass wasted deposits. Some profiles exhibit convoluted properties which could place them in the Cryosolic order. The physico‐mineral‐chemical properties of soils/paleosols in recessional deposits across this sequence provide weathering indices over the mid to Late Holocene in the Swedish sub‐Arctic climate. It is likely the middle group of deposits represents stillstand of the retreating glacier offset by climatic deterioration with the onset of Early Neoglacial climate which altered the glacial mass balance, at least until termination of the LIA. Correlation to other alpine areas in the middle and tropical latitudes with similar records is attempted and discussed. While the Stabre Glacier disappeared after the LIA, the nearby Tärna Glacier remains extant on the land surface, a presumed result of slight elevation differences between the two cirques which affects storm tracks and resultant variations in glacial mass balances.  相似文献   

浅析钻孔灌注桩后注浆技术在河流冲积地层高层建筑中的应用     

邱玲智  王健 《中国勘察设计》2012,(8):77-80

介绍了钻孔灌注桩后注浆(桩端后注浆)在河流冲积地层高层建筑工程中的应用,并和钻孔灌注桩作了对比分析,通过现场单桩竖向抗压静载荷试验和现场低应变试验结果表明,钻孔灌注桩后注浆在此工程中是可行的,并具有较好的经济效益和社会效益。  相似文献   

Numerical simulation of the seismic behavior of self-centering steel beam-column connections with bottom flange friction devices     

Tong Guo  Lianglong Song  Guodong Zhang 《地震工程与工程振动(英文版)》2011,10(2):229-238

A new type of steel moment resisting frame with bottom ? ange friction devices (BFFDs) has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening /closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to f...  相似文献