排序方式： 共有11条查询结果，搜索用时 15 毫秒
1.
The pressure grouting of drilled shaft tips has become popular worldwide due to its effectiveness in mobilizing a larger portion of the available tip resistance under service displacements. This paper presents experimental and numerical studies on the load transfer mechanism and factors controlling the axial response of base grouted drilled shafts in cohesionless soils. The study found that the increased axial capacity of grout-tipped drilled shafts under service loads and displacements depended mainly on preloading effects and the increased tip area provided by the grouting process. A simple prediction approach for estimating the tip capacity of grouted shafts utilizing cone penetration resistance was suggested based on the results of the study. The validity of the proposed approach was verified by the analysis of full-scale case studies of grouted shafts reported in the literature. 相似文献
2.
3.
Dhanya Pushpadas P. Vethamony K. Sudheesh Smitha George M. T. Babu T. M. Balakrishnan Nair 《Meteorology and Atmospheric Physics》2010,109(3-4):91-106
A high-resolution mesoscale numerical model (MM5) has been used to study the coastal atmospheric circulation of the central west coast of India, and Goa in particular. The model is employed with three nested domains. The innermost domain of 3 km mesh covers Goa and the surrounding region. Simulations have been carried out for three different seasons—northeast (NE) monsoon, transition period and southwest (SW) monsoon with appropriate physics options to understand the coastal wind system. The simulated wind speed and direction match well with the observations. The model winds show the presence of a sea breeze during the NE monsoon season and transition period, and its absence during the SW monsoon season. In the winter period, the synoptic flow is northeasterly (offshore) and it weakens the sea breeze (onshore flow) resulting in less diurnal variation, while during the transition period, the synoptic flow is onshore and it intensifies the sea breeze. During the northeast monsoon at an altitude of above 750 m, the wind direction reverses, and this is the upper return current, indicating the vertical extent of the sea breeze. A well-developed land sea breeze circulation occurs during the transition period, with vertical extension of 300 and 1,100 m, respectively. 相似文献
4.
P. Vethamony V. M. Aboobacker K. Sudheesh M. T. Babu K. Ashok Kumar 《Natural Hazards》2009,49(2):411-420
The Ministry of Shipping desires to revise the inland vessels’ limit (IVL) notification based on scientific rationale to improve
the safety of vessels and onboard personnel. The Mormugao port region extending up to the Panaji was considered for this pilot
study. Measured winds and wave parameters (AWS and moored buoy) as well as NCEP re-analysis and NCMRWF winds were used for
the analysis and input to regional and local models. The results of wave model were validated with measured significant wave
heights (SWHs) and the comparison shows a good match. The analysis indicates that SWHs do not exceed 2.0 m during non-monsoon
months, and in monsoon months exceed 5.0 m, and even 7.0 m, especially during extreme events. In order to draw IVL contours
for Goa coastal region, local model was set up and nearshore waves were simulated for the period May 2004–May 2005. Based
on the nearshore SWH distribution, IVL contours have been fixed for the Mormugao port and Panaji coastal regions. 相似文献
5.
6.
P.K. Dinesh Kumar R. Manimurali M.T. Babu K. Sudheesh P. Vethamony K.R. Naveen Kumar 《自然地理学》2014,35(5):411-428
An in-depth analysis has been made to simulate hydrodynamic scenarios for understanding the nearshore sediment transport controls of placer mineral depletion at Manavalakurichi, India. From the analyses of topographic configuration (extracted from Hydrographic Nautical Chart No. 2048 and data generated during year 2010), we inferred that the 5-m isobaths had broadened and exhibited shallowness. Distances between the coastline and the isobaths were found to have increased significantly over the past five decades. Along with this, the 10 and 20-m contours were found to have shifted about 35–100?m horizontally landward. These changes led to severe sediment deposition in these regions due to the changed wave energy levels and refraction patterns. Numerical simulations linking bathymetry, hydrodynamics, sediment load, and significant wave heights revealed that changes in bathymetry would amplify the wave heights and convergence of wave energy. Associated removal of sand from the high-energy zones will eventually lead to sediment starvation situations and depletion of placers in the adjacent beaches. As the observed trends of depletion generate great concern, detailed oceanographic investigations should be taken up immediately in the region. Fine-resolution hydrodynamic data-sets should prove useful for further evaluating the physical responses of the system to the altered geometry and for exploring remedial measures for restoring the heavy mineral content of the beach sand. 相似文献
7.
The classical extreme value theory based on generalized extreme value (GEV) distribution and generalized Pareto distribution (GPD) is applied to the wave height estimate based on wave hindcast data covering a period of 31?years for a location in the eastern Arabian Sea. Practical concern such as the threshold selection and model validation is discussed. Estimates of wave height having different return periods are compared with estimates obtained from different distributions. On comparing the distributions fitted to the GEV with annual maximum approach and GPD with peaks over threshold approach have indicated that both GEV and GPD models gave similar or comparable wave height for the study area since there is no multiple storm event in a year. Influence of seasonality on wave height having different return period is also studied. 相似文献
8.
The use of natural fibers such as coir for soil improvement is highly attractive in countries where such materials are locally and economically obtainable, in view of the preservation of natural environment and cost effectiveness. This paper discusses shear strength of clay reinforced with randomly distributed coir fibers based on a series of consolidated undrained triaxial compression tests. Test results show that major principal stress at failure for clay-coir fiber matrix increases with increase in fiber content (W f ) and fiber aspect ratio (A r ). For all the combinations of fiber contents and aspect ratios, failure principal stress envelope exhibits a curvilinear variation with a transition at a confining stress, known as critical confining stress. Separate regression analyses have been performed for observations below and above critical confining stress to develop mathematical models, which consider fiber content, aspect ratio, confining stress and plain soil characteristics as the input parameter, to predict major principal stress at failure for the clay-fiber composite. In general, the study identifies that the inclusion of discrete coir fibers in random fashion significantly improves the shear strength of clay and hence could be effectively used for the cases where in-place mixing of soil with fibers is possible (e.g., pavement sub-grade, landfill liner, small embankment). The developed regression models may be used in the design phase for the rough estimation of shear strength of the composite. 相似文献
9.
Spectral and statistical wave parameters obtained from the measured time series wave data off Paradip, east coast of India
during May 1996–January 1997 were analysed along with MIKE 21 spectral wave model (SW) results. Statistical wave parameters
and directional wave energy spectra distinctly separate out the wave conditions that prevailed off Paradip in the monsoon,
fair weather and extreme weather events during the above period. Frequency-energy spectra during extreme events are single
peaked, and the maximum energy distribution is in a narrow frequency band with an average directional spreading of 20°. Spectra
for other seasons are multi-peaked, and energy is distributed over a wide range of frequencies and directions. The NCEP re-analysis
winds were used in the model, and the results clearly bring out the wave features during depressions. The simulated wave parameters
reasonably show good match with the measurements. For example, the correlation coefficient between the measured and modelled
significant wave height is 0.87 and the bias −0.25. 相似文献
10.
Tidal eddies in a semi-enclosed basin: a model study 总被引：1，自引：0，他引：1
A modeling study has been carried out to support a Marine Management Plan for the Gulf of Kachchh, India and here the hydrodynamic part of the programme is described. The hydrodynamic model accurately predicts the tides and tidal currents present in the Gulf and these have been validated with the measured data, albeit at only a few locations. The time averaged residual currents obtained from the model for one lunar cycle clearly reproduce the complex, small-scale, topographically induced flows with several eddies. The existence of a dynamic barrier along Sikka-Mundra section, which divides the Gulf into two distinct dynamic systems, is very evident. The model is further used to predict the movement of surface floating particles launched at different locations in the Gulf, as an aid to determining floating pollutants. The results indicate that industries discharging wastes upstream of the barrier should use extreme caution, as these will remain in the vicinity for at least one lunar cycle. 相似文献