Measurement of In Situ Hydraulic Conductivity and Coefficient of Consolidation with Prefabricated Vertical Drains

2004 ◽  
Vol 1874 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Andrea L. Welker ◽  
Brian J. Devine ◽  
R. Robert Goughnour ◽  
Jimmy Foster
Keyword(s):  
Hydraulic Conductivity ◽  
Coefficient Of Consolidation ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains

scholarly journals Research on Horizontal Coefficient of Consolidation of Vietnam’s Soft Soil

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Nu Nguyen Thi ◽  
Bui Truong Son ◽  
Do Minh Ngoc
Keyword(s):  
Experimental Study ◽  
Laboratory Tests ◽  
Soft Soil ◽  
Coefficient Of Consolidation ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Constant Rate ◽  
Different Types ◽  
Cell Test ◽  
Dissipation Test

The horizontal coefficient of consolidation is the most important parameter for designing the improvement of soil soft by prefabricated vertical drains (PVDs) combined with surcharge and vacuum preloading. This paper presents the experimental study on the horizontal coefficient of consolidation (ch) of some soft soils distributed in Vietnam. The ch value was determined by the laboratory test and CPTu dissipation test. The laboratory tests included the Rowe consolidation cell test and constant rate of strain consolidation with radial drainage test. Two types of consolidation laboratory tests were performed. The experimental results indicated that the ch value is always larger than the vertical coefficient of consolidation of soil (cv). The ratio of ch/cv depends on the consolidated pressure, type of soil, and the anisotropy of soil. The ratio of ch/cv is different in different types of soft soil in Vietnam. In the normally consolidated state, the ch/cv ratio ranges from 1.35 to 10.59. It was necessary to choose the ch value at the consolidated stress level for calculating the PVD spacing.

Evaluation of the Effectiveness of Prefabricated Vertical Drains Using Full-Scale In Situ Staged Dynamic Testing

2010 ◽  
Author(s):  
Antonio Marinucci ◽  
Ellen M. Rathje ◽  
J. Scott Ellington ◽  
Brady R. Cox ◽  
Farn-Yuh Menq ◽  
...  
Keyword(s):  
Dynamic Testing ◽  
Full Scale ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains

Probabilistic analysis of consolidation with prefabricated vertical drains for soil improvement

1998 ◽  
Vol 35 (4) ◽  
pp. 666-667 ◽  
Author(s):  
H P Hong ◽  
J Q Shang
Keyword(s):  
Soil Improvement ◽  
Uncertain Parameter ◽  
Uncertain Parameters ◽  
Coefficient Of Consolidation ◽  
Consolidation Process ◽  
Expected Cost ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
Drain Spacing ◽  
Degree Of Consolidation

Prefabricated vertical drains are often used to accelerate the consolidation and to gain strength in soft clayey soils. The consolidation process depends on several uncertain parameters including the coefficients of consolidation and coefficients of permeability in vertical and horizontal directions and the discharge capacity of the vertical drains. A sensitivity analysis of the degree of consolidation to these uncertain parameters is presented for clayey deposits. Results of the analysis suggest that the most important uncertain parameter that affects the consolidation process is the horizontal coefficient of consolidation. The implication of this uncertain parameter in the design of prefabricated vertical drains for soil improvement is discussed. Two approaches are proposed for selecting drain spacing employing a design value of the horizontal coefficient of consolidation. One of the approaches is probability based and the other is minimum expected cost based.Key words: consolidation, prefabricated vertical drains, drain spacing, probability, expected cost, optimal design.

scholarly journals Numerical Investigation to the Effect of Suction-Induced Seepage on the Settlement in the Underwater Vacuum Preloading with Prefabricated Vertical Drains

2021 ◽  
Vol 9 (8) ◽  
pp. 797
Author(s):  
Shu Lin ◽  
Dengfeng Fu ◽  
Zefeng Zhou ◽  
Yue Yan ◽  
Shuwang Yan
Keyword(s):  
Practical Implication ◽  
Soil Surface ◽  
Small Strain ◽  
Seepage Flow ◽  
Excess Pore Pressure ◽  
Combined Effects ◽  
Vacuum Preloading ◽  
Prefabricated Vertical Drains ◽  
Vertical Drains ◽  
The Difference

Vacuum preloading combined with prefabricated vertical drains (PVDs) has the potential to improve the soft sediments under water, however, its development is partly limited by the unclear understanding of the mechanism. This paper aims to extend the comprehension of the influential mechanism of overlapping water in the scenario of underwater vacuum preloading with PVDs. The systematic investigations were conducted by small strain finite element drained analyses, with the separated analysis schemes considering suction-induced consolidation, seepage and their combination. The development of settlement in the improved soil region and the evolution of seepage flow from the overlapping water through the non-improved soil region into improved zone are examined in terms of the build-up of excess pore pressure. Based on the results of numerical analyses, a theoretical approach was set out. It was capable to estimate the time-dependent non-uniform settlement along the improved soil surface in response to the combined effects of suction-induced consolidation and seepage. The difference of underwater and onshore vacuum preloading with PVDs is discussed with some practical implication and suggestion provided.

scholarly journals Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1131
Author(s):  
Soonkie Nam ◽  
Marte Gutierrez ◽  
Panayiotis Diplas ◽  
John Petrie
Keyword(s):  
Hydraulic Conductivity ◽  
Field Measurements ◽  
Natural Soil ◽  
In Situ Tests ◽  
Seepage Analysis ◽  
Soil Deposits ◽  
Seepage Modeling ◽  
Sample Disturbance

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.

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