Practical Field Investigations on Permeability by Means of Water Pressure Tests

Rock Grouting ◽  
1985 ◽  
pp. 276-299
Author(s):  
Friedrich-Karl Ewert
Keyword(s):  
Water Pressure ◽  
Field Investigations ◽  
Pressure Tests ◽  
Practical Field

3D Numerical Analysis of Seismic Performances of Dyke on Liquefiable Soils

2011 ◽  
Vol 243-249 ◽  
pp. 3824-3831
Author(s):  
Ming Wu Wang ◽  
Guang Yi Chen
Keyword(s):  
Pore Water Pressure ◽  
Numerical Models ◽  
Water Pressure ◽  
Silica Sand ◽  
Three Dimension ◽  
Seismic Safety ◽  
Mechanism Model ◽  
Centrifuge Tests ◽  
Field Investigations ◽  
Effective Stress Analysis

Many field investigations of earthquake disaster cases confirm that earthquake-induced liquefaction is a main factor resulting in large damages to dyke. Consequently to ensure seismic safety of dyke on the liquefiable foundation, the research on seismic performances of dyke is of great importance. Herein seismic responses of dyke on the liquefiable soils were discussed by means of three dimension effective stress analysis method using a multiple shear mechanism model and liquefaction front. Two numerical models, in which the liquefiable foundation both consisted of saturated fine silica sand of 30% relative density and scenario waves with peak amplitude of 0.8056 and 3.133 m/s2 were used input waves, were conducted to investigate the distribution principles and the changing rules of deformation, acceleration, express pore water pressure, and shear dilatancy behavior in the dyke and the liquefiable foundation. The computed results do good agreements with the measured results from centrifuge tests. And these results may be of theoretical and realistic significance for seismic design of dyke on liquefiable soils.

Hydraulic Conductivity and Scale Effects Investigation in Basalt in the Dam Area of Xiluodu Hydroelectric Station, Jinshajiang River, China

2013 ◽  
Vol 405-408 ◽  
pp. 2123-2129
Author(s):  
Yuan Yao Li ◽  
Rong Lin Sun ◽  
Ren Quan Chen
Keyword(s):  
Hydraulic Conductivity ◽  
Scale Effects ◽  
Fractured Rock ◽  
Water Pressure ◽  
Hydroelectric Station ◽  
Tracer Test ◽  
Test Results ◽  
Hydraulic Test ◽  
Water Seepage ◽  
Pressure Tests

Hydraulic conductivity (K) and scale effects in basalt in the dam area of Xiluodu hydroelectric station were investigated by three kinds of field hydraulic tests with different test scale, 2608 water pressure tests in single borehole, 54 water seepage tests in adit and groundwater tracer test. Statistical results show the high heterogeneity of fractured rock and K difference between two neighboring test intervals are often more than two orders of magnitude. However, there is a strong decreasing trend of hydraulic conductivity with the increase of vertical depth. Moreover, these three kinds of hydraulic test results demonstrate that hydraulic conductivity increases with the increase of test scale in heterogeneous basalt and the heterogeneous degree of K decreases with the increase of test scale. K from water seepage test in adit, with the test scale of 1-2 m, is dispersed from 0.00024 m/d to 3.46 m/d. K from water pressure test in single borehole, with the test scale of 4-7 m, is 0.0002-1.04 m/d. K from groundwater tracer test, with the test scale of 70-145 m, is concentrated between 0.46 m/d and 2.1 m/d. High heterogeneity of fractured rock and multi-level of fractures are thought as the major reason resulted in scale effects of hydraulic conductivity.

scholarly journals Developent and Application of Hybrid Method to Inhomogeneous Geology for Curtain Grouting -Case Study in Sedimentary Rock with Fold Movement for Nam Ngiep 1 Hydropower Project in Lao PDR-

2021 ◽  
Author(s):  
Yoichi Yoshizu ◽  
Kazuo Nakamura ◽  
Tatsuya Kawata ◽  
Takahiro Fujii ◽  
Shoji Tsutsui
Keyword(s):  
Conventional Method ◽  
Sedimentary Rock ◽  
Water Pressure ◽  
Lao Pdr ◽  
Hydropower Project ◽  
Dam Foundation ◽  
Mix Proportion ◽  
Pressure Tests ◽  
Curtain Grouting ◽  
The Individual

Abstract Curtain grouting for dam foundation treatment is one of the most crucial work items in dam construction to secure the impermeability of the foundation rock. Some decades ago, the Grouting Intensity Number (GIN) Method developed in Europe has been frequently applied to relatively simple geotechnical structures. On the other hand, the Conventional Method, which requires phased mix proportion and water pressure tests through a sequence of the works, is as yet reliable for inhomogeneous geology. This paper presents the development of a modified curtain grouting method and its application to the Nam Ngiep 1 Hydropower Project in Lao PDR, which has an inhomogeneous geology of sedimentary rock with weak layers affected by fold movement. The method has been dubbed as “hybrid” because it garners both the economical superiority of the GIN Method in that it enables the use of a single mix proportion, and the technical superiority of the Conventional Method in that the individual design pressure in each stage is based on water pressure tests.

Stabilization of Shallow Slope Failures with Lime Piles

1997 ◽  
Vol 1589 (1) ◽  
pp. 83-91 ◽  
Author(s):  
C. D. F. Rogers ◽  
S. Glendinning
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Shear Plane ◽  
Slope Failures ◽  
Field Investigations ◽  
Surface Data ◽  
Access Problems ◽  
The Subject ◽  
Increased Strength ◽  
Clay Slopes

Lime piles essentially consist of boreholes filled with lime. They have been used to stabilize slopes in many countries worldwide but have not been adopted as a standard means of stabilization in any country. The literature on the subject makes several claims about the way lime piles stabilize the soil. However, the reported results of experimental work are in some cases contradictory and are too few to facilitate appropriate engineering judgment of the stabilizing mechanisms. Research at Loughborough University, United Kingdom, has investigated the use of quicklime piles in the context of stabilization of shallow slope failures in clay slopes. The stabilizing mechanisms observed in a series of laboratory and field investigations are ( a) increased strength of an annular zone of clay surrounding the pile caused by lime-clay reaction, ( b) clay dehydration, ( c) generation of negative pore-water pressure, ( d) over-consolidation of the soil in the shear plane, and ( e) pile strength. The idea of lateral consolidation of the clay surrounding the pile as a result of physical pile expansion has been shown not to occur in the case of augured quicklime piles sealed with a clay plug at the surface. Data are presented to quantify each of the stabilization mechanisms and advice is given on how to use the data in design. It is concluded that lime piles provide a potentially valuable addition to the techniques available for shallow slope stabilization and are particularly suitable for sites with access problems.

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