夯击能应用于高填土地基的一些探讨   总被引：2，自引：0，他引：2  

涂齐亮  王清  李振  夏玉斌 《工程地质学报》2002,10(4):395-399

大量工程实践表明 ,对填土及软土地基进行夯击加固时 ,夯击能的选取不仅与填土层的厚度有关 ,而且与填土层下覆土质的工程地质条件等因素密切相关。本文结合南方某港口填土地基加固工程实例 ,对在高填土地层中夯击能的使用问题进行了探讨 ,分析了当填土层的下卧层分别为坚硬土层和软弱土层、以及当填土层的填料分别为粗颗粒料和含水量较高的粘性土等细粒填料时 ,填土层加固的机理 ,制定了在不同条件下选取夯击能的标准 ,并根据现场检测资料 ,评价了该场地的地基加固效果 ,进一步验证了所确定夯击能标准的可靠性。  相似文献   

第五代CT——超高速CT     

黄明子 《CT理论与应用研究》1992,(4)

超高速X线CT的动态摄影、三维图象的构成,临床上的作用已引起医学界的关注。本文将就超高速CT 装置的结构、性能、扫描法,临床应用作一介绍。  相似文献   

降雨对尚志井水位动态影响的剖析     

鱼金子  车用太  张大维  许学礼  毕志铭  刘丹  蒙爱民  宇振和 《东北地震研究》1992,(4)

本文系统研究了降雨量、降雨方式等对尚志井水位年、季、日动态的影响,指出了降雨是该井水位动态的主要影响因素,剖析了这种影响的特征。此外,还提出了东北地区深井水位早春回升的“冻层底部消融”补给机制的新观点。  相似文献   

发展地球科学大体系理论开拓人类文明的新前景     

陈荫祥 《遥感学报》1991,(3)

从人类发展需要及科学理论趋势出发论述地球科学各门类的大体系综合理论跃迁的观点。提出以地球深源岩浆热动力为主链的岩石圈、水圈、大气圈和生态环境圈的总体物质——热力运动高统帅性理论。展望新的高技术观(监)测系统。  相似文献   

科学发展动力学模型与学术带头人培养     

杜志俊  钱效魁等 《华南地震》1991,11(4):83-89

本文将物理学上力学系统的运行与科学发展进程对比，提出了科学发展的动力学模型，运用这一模型分析了国家地震局系统的学术带头人队伍现状及进一步发展应解决的问题。科学发展能力可近似为三种基本力。本文针对地震系统的具体情况，定量给出了三种力的作用方式，相应的动力学近似为三种基本力。本文针对地震系统的具体情况，定量给出了三种力的作用方式，相应的动力学模型，并就模型涉及的科学惯性问题、科学能力的有机构成问题，以及系统可控性问题、反馈问题等做了一此讨论，进而指出了如何加速系统、增大产出（科研成果等）、培养创造型人才及学科带头人的可能途径。  相似文献   

水土流失区土地利用动态的遥感监测——以晋西三川河流域为例     

乔玉良 《遥感学报》1992,(3)

本文以晋西三川河流域为试验区,利用不同时期的航空像片,采取集群抽样法,借助计算机建立信息数据库,并统计计算和辅助制图,进行土地资源动态监测,查清这一中型流域23年来土地利用动态变化情况及水土保持综合治理效益。  相似文献   

The role of wavegroup velocity in the blocking problem     

Martin Dunst 《Pure and Applied Geophysics》1977,115(3):459-471

Considering the blocking problem as a baroclinic instability problem in a dispersive wave system with diabatic heating effects, it is of great interest to investigate the role of wavegroup velocityv _gr in blocking processes, becausev _gr controls the energy transfer in the wave field. Using a Newtonian Cooling —type of forcing with a phase differencek to the main field and taking the linearized version of a two-level model, the phase speedc _r, the group velocityv _gr and the growth ratekc _i have been obtained as analytical functions of the mean zonal windU, the thermal windU _T, the coefficient of diabatic heating x, the phase differencek and the wavelengthL. Now the hypothesis is introduced, that a blocking should be expected, ifv _gr has a maximum value in the vicinity ofL _o, for whichc _r vanishes and thee-folding timet=1/kc _i (kc _i>0) is smaller than 6 days (see condition (20) in the text). One finds, that for special parameter combinations (U _T, U, ), where 15 m/secU _T25m/sec,U=10m/sec, 0.8·10^–51.5·10^–5 [sec^–1], certain valuesL _o with an appropriate phase differencek exist, which satisfy the conditions mentioned above (for values see Table 2). TherebyL _o varies within the range 8500 km <L _o<11000 km corresponding to the preferred planetary blocking wavenumber 2 in middle latitudes 50°<<70° N.  相似文献   

Observations of contemporary arroyo cutting near Santa Fe,New Mexico,U.S.A.     

Harold E. Malde  Arthur G. Scott 《地球表面变化过程与地形》1977,2(1):39-54

Arroyo cutting that began in the American Southwest in the 1880s is associated with sudden runoff, a circumstance characteristic of this semiarid region in which occasional intense rainfall exceeds the capacity of the ground to absorb water. This report describes two arroyos in an area of moderately dissected bolson deposits southwest of Santa Fe, Cañada de la Cueva and Pueblo Cañon, where arroyo cutting since 1970 has been closely related to runoff from summer rain. The area is vegetated chiefly by grama grass and scattered juniper. Cutting is monitored by repeated surveys of channel floors, cross-sections, and headcuts, and by repeated photographs taken as stereopairs. Rainfall and discharge are measured simultaneously in 5-minute intervals by dual digital recorders at a gauging station on Cañada de la Cueva (drainage area 4.64 km²). Discharge has been as much as 18.2 m³/s from rainfall of 25.2 mm. The maximum 15-minute intensity for this storm was 64.0 mm/hr, and runoff was 7.9 mm. The flood peak arrived in 20 minutes, by which time 80 per cent of the rain had fallen, and the flow subsided to a tenth of its maximum in less than an hour. This storm at Pueblo Cañon (drainage area 13.3 km² above the place of measurement) resulted in an estimated discharge of 140 m³/s, and features produced by hail on the channel floor suggest that the duration of flow could have been as brief as 30 minutes. Observed increments of headward cutting at Cañada de la Cueva range from 0.28 m for 1.8 mm of runoff to 4.9 m for 12 mm of runoff. Aggregate cutting in 5 years has been as much as 13.7 m, resulting in erosion of 570 m³ of alluvium. Headward cutting near the mouth of Pueblo Cañon has been observed in increments of 10.3, 14.6, and 20.7 m, for an aggregate of 45.6 m, as measured from 1971 to 1974. This cutting removed 1,770 m³ of alluvium.  相似文献   

Test of scale modelling of sediment transport in steady unidirectional flow     

John B. Southard  Lawrence A. Boguchwal  Richard D. Romea 《地球表面变化过程与地形》1980,5(1):17-23

In two steady uniform flows at different physical scales in a small open channel, with variables characterizing flow, sediment, and fluid adjusted for dynamic similitude by means of four dimensionless modelling parameters (a Reynolds number, a Froude number, a density ratio, and a length ratio), measured frequency distributions of height, spacing, and migration rate of current ripples were almost identical when scaled, thus verifying that exact Reynolds-Froude modelling of loose-sediment transport is valid and workable. Modelling should be valid as well for a wide range of other transport conditions in the same kind of flow, because no additional kinds of forces or effects would be present in transport of loose grains in modes other than as ripples. In scaled-down modelling, a scale ratio of 2.5 is attainable without recourse to exotic fluids by use of water at 85°C to model natural flows at 10°C.  相似文献   

Dynamic Response of Shallow-Buried Tunnels Traversing High Loess Slopes     

SUN Wen  LIANG Qingguo  WANG Lili  CAO Xiaoping 《中国地震研究》2020,34(4):496-509

Considering the existence of numerous shallow-buried tunnels traversing high slopes in the loess area in western China and the fact of high seismic intensity there, we investigate the dynamic response rules of a shallow-buried loess tunnel and its slope under the action of seismic waves with different intensities. Through large-scale shaking table model tests,we successfully analyze the characteristics and process of the destabilization of tunnels and slopes, and propose valuable suggestions regarding the reinforcement parts of a tunnel for reducing seismic damage. The results show that the main seismic damage on a slope include the failure of the sliding surface between the top and foot and the stripping of the soil around the tunnel entrance, while the damage on a tunnel is mainly manifested as the seismic-induced subsidence at the portal section and the cracking deformation at the joint areas. Finally,we propose that the "staggered peak distribution" phenomenon of the maximum acceleration values at the vault and inverted arch area can be considered as a criterion indicating that the tunnel enters into the threshold of dynamic failure.  相似文献