Effect of Pore Pressure Dynamics on Progressive Failure in a Clayey Glaciolacustrine Landslide

Actual geotechnical monitoring systems and models of geocryological processes are aimed at assessing and preventing hazardous dynamic impacts on infrastructure facilities in the Arctic and Subarctic of Russia. The level of methodological support and hardware development of these systems are insufficient in Russia in the context of a changing climate, growing environmental impact and decreasing quality of geological survey and design. Pore pressure is successfully studied at the sample level in the laboratory and in the field by using the static sensing method, however, the dynamics of pore pressure and the physical patterns of this dynamics in soil massifs remain studied inadequately. For theoretical reasons, pore pressure should change under the influence of processes associated with freezing and thawing, and, consequently, it should affect the intensity of gas hydrate dissociation as well as the mechanical properties of soils. The modern technological base provides new opportunities for the study of the pore pressure dynamics in the soil mass. This opens prospects for improving geotechnical monitoring systems for the protection of infrastructure facilities from adverse natural and man-made impacts.

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Performance of a test embankment constructed on an organic clayey silt deposit

Canadian Geotechnical Journal ◽

10.1139/t01-051 ◽

2001 ◽

Vol 38 (6) ◽

pp. 1283-1296 ◽

Cited By ~ 5

Author(s):

R Kerry Rowe ◽

C T Gnanendran ◽

A J Valsangkar ◽

A O Landva

Keyword(s):

Pore Pressure ◽

Progressive Failure ◽

Limit Equilibrium ◽

Pressure Response ◽

Equilibrium Analysis ◽

Classical Type ◽

3D Analysis ◽

Clayey Silt ◽

Pore Pressure Response ◽

Test Embankment

The instrumentation, construction, and field performance of a full-scale test embankment constructed on a soft compressible organic clayey silt is described. The construction sequence, the observed vertical and horizontal displacements, and the pore pressure response are presented. The embankment behaved elastically up to a thickness of about 3.65 m. The settlement and heave responses suggested that the embankment approached failure at a thickness of about 6.1 m and a corresponding net height of 5.4 m. The failure was gradual and of a viscoplastic type, and no classical-type abrupt failure was encountered during the construction of this embankment. The height to which the embankment could be constructed was lower than the 711.4 m range expected from conventional two-dimensional (2D) limit equilibrium analysis based on vane strength data. This, coupled with the pore pressure response, suggests that a combination of progressive failure and the influence of the adjacent reinforced section constructed to failure may have been significant factors affecting the performance of this embankment. Thus, the data reported in this paper can be used as a test case for developing three- dimensional (3D) analysis methods wherein the constitutive model can be truly tested for 3D conditions involving the interaction between embankment sections that are constructed under different conditions.Key words: embankment, field behaviour, stability, deformations, pore pressures.

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Stratigraphic profiling, slip surface detection, and assessment of remolding in sensitive clay landslides using the CPT

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0171 ◽

2021 ◽

Author(s):

Joshua Potvin ◽

David Woeller ◽

James Sharp ◽

W. Andy Take

Keyword(s):

Pore Pressure ◽

Slip Surface ◽

Progressive Failure ◽

Cone Penetration ◽

Cone Penetration Testing ◽

Tip Resistance ◽

Sensitive Clay ◽

Pore Pressure Response ◽

Soil Behaviour ◽

Intact Soil

A multi-year cone penetration testing program was initiated at a landslide subject to episodic retrogression in Mud Creek, Ottawa, to assess whether a hand-operated mobile CPT could yield new insights into the current degree of remoulding under progressive failure in metastable areas of a landslide where conventional tracked rigs are unable to gain access. The mobile CPT rig permitted tests to be performed through the entire thickness of the Champlain Sea deposit at a penetration rate of 0.5 cm/s, with similar results to tests performed at the standard 2 cm/s. Measurements of pore pressure varied considerably with cone size, with the magnitude of pore pressure response decreasing with cone size. The elevation of the slip surface was identified in the tip resistance as the point of transition between the remolded soil above the slip surface and the intact soil below the slip surface, whereas a further 0.5 m of penetration was required to elevate pore pressures to values indicative of the intact soil behaviour. In-situ measurements of shear strength of corresponding layers between the intact and remolded profiles to be compared indicating that the soil above the slip surface had remolded to 50% of its fully remolded strength.

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