Use of an impact penetrometer for the evaluation of the in‐situ strength of marine sediments

Abstract

A description is given of the method used in evaluating the in-situ strength properties of soil from the results of impact penetrometer tests. The test results presented include both laboratory tests, conducted under controlled conditions, and field tests, obtained with a Marine Impact Penetrometer developed for shallow sub-bottom depth exploration. The test results indicate that with this system the dynamic strength profile and the soil type, thickness and depth of different layers can be directly evaluated up to the final depth of penetration. The depth of penetration obtained is a function of mass and geometry of the penetrometer and the subbottom soil conditions but a 1000 lb (453 kg) penetrometer should be capable of 50 ft (15 m) penetration in soft sediment. If a soil viscosity coefficient is correctly estimated, the static strength profile can be obtained from the dynamic strength profile by applying a correction for penetration rate effects. IntroductionThe ocean floor is one of the last unexplored frontiers on the earth. In recent years, a tremendous interest has been generated in its exploration for both military and civilian purposes. One fact is clear, increasing demands associated with an increasing population necessitates that technology turn to the ocean for food, energy, and other resources.The design of foundations for seafloor installations as well as most other applications of soil mechanics to marine work requires detailed information on

Cone penetration testing to assess slope stability in the 1979 Nice landslide area (Ligurian Margin, SE France)

“…Dynamic-CPTU tests, with high penetration rates up to 10 m/s, show higher values compared to the static-CPTU parameters, and thus have to be corrected for this so-called strain-rate effect (e.g. Dayal et al 1975, Stoll et al 2007, Steiner et al 2012. Previous studies illustrate that the modified inverse sin-hyperbolic equation, comprising the ratio of the dynamic and static penetration rate (vdyn and vref) as well as SSC, is best suited for the strain-rate correction of clays (e.g.…”

Terminal depth of penetration of spherical projectiles in transparent granular media

“…Penetrators, as a means of probing soil properties, have also been used in geotechnical engineering [7,12,33,36]. Additionally, craters caused by hypervelocity impact of meteors, has been of interest to both terrestrial and planetary geologists [23].…”

Construction and use of an inexpensive, lightweight free-fall penetrometer: applications to paleolimnological research

“…This oscillation is a consequence of the elastic properties of the sediment and, if present can be used to quantify the shear strength of that sediment (cf. Dayal et al 1975). (B) Figure 4.…”

“…Penetrometers have long been used to measure the physical properties of sediments in situ (Dayal et al 1975;Chari et al 1979;Akal and Stoll 2002), most commonly the undrained shear strength and relative density of sea floor sediment (Dayal 1981;Akal and Stoll 2002). Penetrometer data support a variety of applications including seabed classification, geotechnical site investigation, dredging surveys, and naval applications.…”

“…In situ designs are, in general, lowered to the lake bed and use the depth of penetration of modified weighted rods to characterise lake sediment properties (Gaugush 1998). Free-fall designs impact the lake bottom and use acceleration and, in some cases, pressure sensors to monitor the sediment response to penetration (Dayal et al 1975). Several types of free-fall penetrometers exist.…”