Marine geotechnical studies at continental margins: a review—Part I

Marine geotechnical studies at continental margins: a review - - Part I* GIDEON ALMAGOR Marine Geology Division, Geological Survey of Israel, Ministry of.Energy amt Infrastructure, Jerusalem, Israel

SCOPE O F MARINE SOIL E N G I N E E R I N G The oceanographic data that have been collected throughout the last decades demonstrate that the geological processes in the oceans, especially those taking place in the continental margins, are dynamic and highly variable. Areas of the seafloor once thought to be barely active or immobile are now known to undergo changes at rates that are sometimes startling t. Until recently the published literature on sttbmarine soils has been written by geologists who were mainly interested in the processes that shaped the submarine morphology, and consequently, mapping, description, identification and dating of the sediments constituted the main topics of the marine geological research. The bulk of the research that was carried out was, therefore, descriptive in nature, and although it generated ideas of utmost importance to the development of the earth sciences, our understanding of the mechanisms of many of the geological processes is still very incomplete, or sometimes completely lacking, because ofthe deficiency in precise quantitative data. Quantification of numerous submarine processes and of the conditions under which they occur, such as the effects of deposition, erosion, diagenesis and lithification of the seafloor sediments, sediment stability or the lack of it, and soil movements such as creep, slumps and slides or turbidity currents, are vital to our understanding. Many of these processes are highly hazardous, and therefore, the development of reliable predictive models of sediment movement and sediment behaviour under various environmental conditions is necessary. This is clearly demonstrated by the amotlnt of structural damage attributable to sediment failure in the oil production area of the Mississippi Delta front ~'2. Marine geotechnology is a multidisciplinary science that attempts to define and understand the scientific and engineering aspects of seafloor sediments including physical, mechanical, chemical, biological and acoustic properties that affect the electrolyte-gas-solid sedimentary system, and the response of this system to applied static and dynamic forces. Although the marine environment imposes heavy physical and economic constraints, and although several environmental and compositional differences between tcrrestrial and marine sediments exist (i.e., high content of skeletal material and ,organic debris, saline pore water, high pressures and low temperatures, and very different rates of deposition) marine geotechnology essentially uses the same * This review was submitted to the Special Committee on Oceanic Research (SCOR) Working Group 61 on Sedimentation at Continental Margins for presentation at its first meeting in December 1979, in Canberra, Australia.

0141 - l 1 8 7 / 8 2 / 0 2 0 0 9 1 - 0 8 $ 2.00

(~-)1982 CML Publications

methodologies as those ct, rrently used on land. The major differences between geotechnical engincering in the marine environment and that on land are in sampling and in situ measurement techniques, underconsolidation (or excess pore-water pressure in the sediment), 'apparent overconsolidation', gas in sediments and dynamic loading effects3.'-t. This article is based on the existing literature. The relevant marine geological-geophysical literature and soil mechanics and foundation engineering literature were recently surveyed by Richards et al. 5 and Davie et al. 6. The purpose of the present article is to familiarize marine geologists with the major concepts of marine geotechnological research related to sedimentation processes at continental margins, to briefly review the present knowledge, to point out major deficiencies in the present knowledge, and to recommend guidclines of research that ought to be undertaken to fill them. TYPES, DISTRIBUTION AND CONSISTENCIES O F SUBMARINE SEDIMENTS In the general engineering sense, soil is any unconsolidated material composed of discrcte solid particles and interstitial gas and/or liquids 7. To the geologist, sediment is a deposit formed by means of water, wind or ice and is a product of chemical, biological, and physical weathering of solid material on the earth's surface. The terms soil and sediment are used interchangeably in this review, depending on whether the context of discussion is engineering or geological. Marine sediments (soils) are characteristically saturated with pore water. However, in certain anaerobic environments gasladen sediments are found. The bulk of tile marine sediments is detrital, hence the classification of marine sediments is commonly based on grain-size, the major groups being gravel, sand, silt arid clay (Fig. 1). This classification separates soils into gramdar or cohesionless soils and finer-grained cohesive soils, which are the fundamental divisions from the engineering point of view. A secondary classification groups cohesive soils according to the degree of resistance they offer to deformation [termed consistem:y) based on their liquid limits and plasticity indices (see below) (Fig. I). Although a detrital sediment could be a mixture of three (evcn four) diffcrcnt size components, in practice such is rarely the case. Most deposits are distinct gravels, sands, silts or clays, and are modified only by the introduction of materials from the preceding or following size grades 8. The sediments of the ocean floor are of terrigenous, biogenic, volcanic, residual and attthigcnic origins, their distribution is related to their sources and transport paths

Applied Ocean Research, 1982, Vol. 4, No. 2

91

Review of marine geoteclmical studies at continental margins(I): G. A lmagor CLAY

SAND

Q

SILT

Decreasing water content

Plasticsolid l

Liquid

Brittle solid

Liquid limit Plastic limit q Plasticity i n d e x - ~

50'

40 "1:3 r 7. 3o 9-t2 20

.::.'..:. ,?: ;.?

~.--~

9

~

t~

~- 1o o o

20

40 60 Liquid limit

cementation, litbification and production of gases; (5) the current regime which determines the dispersal patterns of the sediments, or causes winnowing of fine-grained sediments, non-deposition, or erosion of the bottom sediments resulting in the exposure of relict sediments; (6) mass inot'emems expressed by turbidity currents, slumps and slides, and creep; (7) rise of sea level since the last glacial that resulted in the preservation of extensive areas of Pleistocene coarse-grained relict outcrops on the continental shelf zs. Figure 2 attempts to summarize these processes diagramatically. Frequently, sediments of the same granulometric composition assume different consistencies: silts and sands are loosely or densely packed, and clays appear to be brittle, stiff, cohesive and sticky, soft, etc. The microstructure of the sediment, i.e., the orientation and arrangement (spatial distribution) of its solid particles and the particle-to-particle relationships t3, is dependent to a large degree on the environmental conditions during its deposition and the sedimentary overburden it has supported since its deposition. Where the rate of deposition is slow, the accumulating sand and silt grains tend to roll into a stable position upon arrival at the sediment surface, and form fairly loose packing. Dense packing is formed under the growing overburden of the accumulating sediment or under repeated wave loading. The denseness of a granular soil determines to a large degree its consistency. Relative density (or degree of density) is a comparison of the natural density of a soil with its loose and dense states

9

80

100

-th'-,,,.l-.

' "''"

-,!, ,l,+"+'-

Mt.lmm

~

.m,l s

c

.+

1o,

.4,

q.,

+?.r

,'1:,?.+

:?"" ,-ll, ,i,yFigure I. Classificatioll of sediments (soils). (a) Nomenclature based o~1 saml-siff-clay percemafesg: (b) behaviour of cohesive soil over ranye of water content: (c) plasticity chart I~ are governed by many interrelated environmental processes. Most of the continental shelves and shallow seas are floored with sands that contain various quantities ofskelelal matter, while silts and clays are deposited at the mouths of large rivers, in quiet water behind barriers, in shelf basins ~~and on the continental slope and in the deep sea ~z. The sedimentary environments are discussed in detail in the geological literature t3":+. The major environmental factors and processes that govern distribution of the sediments in the oceans and their consistencies are: (1) provemmce which determines the mineralogical composition of the discrete sediments; (2) prominent depositkmal enriromnents, such as deltas, which determine the quantities and areal distribution of the accumulating sediments; (3) the morphology of the seailoor, such as tectonic or recfa] dams that trap sediments, or submarine canyons that serve as sediment funnels; (4) bioyenic aml chemical acticity that is expressed in the accumulation of skeletal debris of various sizes, rcworking of sediments, and diagenetic processes such as

92

Applied Ocean Resettrch, 1982, 1/ol. 4, No. 2

Figure 2. Schematic cross-section of continental margin-major ent'iromnental factors aml processes that govern distribution of sediments (modified after Emery) t 6

Review of marine geotechnical studies at continental margins(I): G. Almagor

undisturbed sample

sediment sample subjected 2 to normal load of 4 kg/cm

sediment sample subjected 2 to normal load of 64 kg/cm

B in which the clayey flakes assume random spatial orientations. Under accumulating sedimentary load the sediment consolidates, its microstructure becomes better oriented, and the consistency changes depending on its water content (Fig. 3b). If the rate of deposition is high consolidation cannot be accomplished since its pore waters cannot escape through the accumulating overlying sediments due to the sediment imperviousness, which may be reflected in yet a different consistency of the sediment. This matter will be taken up again in later sections. Packing patterns of coarse sediments are adequately treated in every textbook on soil mechanics 23. Clay fabric was recently reviewed, and new data were introduced by Bennett et al. 17.

,

t

A

SAMPLING

Figure 3. most conveniently expressed by: O a = (ema x -- e)/(ema x -- emJ

(1)

where D d is the relative density, and e, emax and eminare, respectively, the natural maximum possible and minimum possible void ratios. Where the rate of deposition is rapid, such as in deltaic environments, and the sediment is silt or fine sand, an equilibrium between the weight of the sinking grains and the adhesive forces of the grains at their contact points may exist, which results in an extraspacious metastable grain packing of the sediments (Fig. 3a) prone to collapse under sudden shocks (liquefaction-see below). Liquefiable soils usually have effective size (i.e., maximum grain size ofthe smallest 109/oof the sample) less than 0.1 mm, relative densities of less than 0.4-0.5, and uniformity coefficient (i.e., ratio of the maximum size of smallest 609/0 to the effective size) of less than 5 2 0 - 2 2 . Changes of microstructure of clayey sediments, which consist of tiny flaky particles that are very active physicochemically, are readily reflected in the high variability of their consistency under different environmental conditions. The consistency of a clayey sediment is greatly dependent on its mineralogical composition, the rate of deposition and the loading history of the sediment. Where the rate of deposition is slow the inter-particle adhesive forces are sufficiently strong to support a relatively spaciously packed structure

Research of both submarine geological processes and underwater construction requires investigation of soil conditions. Rapid and simple procedures for the recovery of undisturbed soil samples are, therefore, vital for marine geotechnological research and practice. In the present article only those methods and procedures of sampling that are relevant to current marine geologicalgeotechnological practices are reviewed in some detail. Comprehensive reviews of the art and treatment of special aspects of underwater sampling were published elsewhere 2., - 2 7 . Except for direct sampling accomplished by divers, whose activity is limited to short working time over small areas at shallow water depths~ underwater sampling is usually remotely accomplished by means of tethered samplers. The methods employed include the following2S:

(A) Methods using tethered devices (1) from water surface, using anchored or dynamically positioned ships and barges or fixed and upjack platforms; (2) by means of tethered bottom-standing platforms and moving submersibles; (3) by tethered bottom crawlers. (B) Methods using free devices (1) from water surface, using free or boomerang corers; (2) by manned submersibles. Sampling from the surface is by far the most extensively practised method, the other methods being severely limited due to complicated procedures, awkward

Applied Ocean Research, 1982, Vol. 4, No. 2

93

Reciew of marine geotechnical studies at continental margins(l): G. A In!ayor penetration into the seabottom, wtrious chambers were devised, such as gas 3s and explosive chambers 36, conveyer chambers to unfurl high tensile and smooth enveloping fabric during sampling, and chambers with compressed fluids to exert self-jetting32. Special corers are equipped with cameras, compasses 37, pressuremeters 38, impact penetrometers 39, transducers 33 and other accessories to carry out special additional measurements.

t e,.,41 ~

fret *kt

i,~ ~ l . * l o Q

m .PI~tA, ~ .

Figure 4. Principle of operation of a piston corer manoeuverability and expenditure involved. Thc latter are not reviewed herein. The present techniques of underwater sampling may be subsumed under two major categories: (1) shallow penetration sampling to depths ranging from a few ccntimetres to several tens of metres below seafloor, and (2) deep penetration drilling to depths of several kilometres bclow scafloor.

Shallow penetration sampling of fine sediments Shallow penetration sampling of fine sediments is accomplished by pushing a sampling device into the seabottom and retrieving the sampler with the sediment sample either by pulling if it is tethered, or by frccing it from an expandable weight assembly and floating the sampler by means of a buoyant chamber29'3~ Penetration is activated by gravity, hydrostatic pressure, or explosion, and takes place in one motion. Various types of samplers have been devised; those mostly used were described by Hopkins 3~ and Rosfelder and Marshall 32. Currently 'undisturbed' samples adequate for geotechnical studies are obtained by open-barrel gravity and piston corers. The corer basically consists of a weight assembly w.ith a barrel attached to its lower part (Fig. 4). The barrel is either cylindrical or rectangular in crosssection. It is several dccimctres to 30 m long (Giant Piston Corer--Silva et al.33), and the diameter may reach 150 mm. The weight imparts to the corer its driving force and maintains the vertical stability of the barrel while falling. Increase of friction between the barrel and the sediment during sampling decelerates penetration until the corer stops. By incorporating within the barrel a piston that remains attached to the lov, ering cable and is adjusted to remain stationary at or slightly above the sediment surface past which the barrel slides into the sediment the frictional forces are significantly ovcrcome, thereby allowing deeper penetration 3"*. Figure 4 shows how the piston corer is operated. A cutter attached to the barrel tip helps penetration; a retainer at the mouth of the barrel prevents loss of the sample; and a valve on top of the gravity corer and the piston which stays at the top of the barrel after sampling prevent the sample from being washed out of the barrel while the corer is hauled up. Other accessories are currently employed, such as fins to stabilize the corer while falling, and devices to trigger free failing a few metres above seafloor to increase velocity and momentum (Fig. 4). In order to facilitate yet deeper 94

Applied Ocean Research, 1982, Vol. 4, No. 2

Mechanical disturbances infine sediments caused by coring High kinetic energy generated by the weight assembly forces the corer into the seabottom 4~ Many times the corer does not penetrate fully. Comparison of the core length to penetration in varied sediments showed that core shortening Occurs 36'42. Comparison between piston cores and simultaneously obtained gravity cores showed that piston cores are subjected to more serious deformation and disturbances 43-a6. Disturbances are expressed mainly in the absence and remoulding of the upper 47-49 and the lower sections of the core samples 4"~, excessive lengths of the lowermost section of the cores S~ thinning or complete absence of soft la3)ers42'st, and changes in mass physical sediment properties.~Z.4~m,..~.~ i -- 5. ~,. Shortening and disturbances in the core samples are caused (1) because it is impossible to immobilize the piston at the scafloor during sampling'*'~'s'*'55; and (2) by the impact of the failing corer on the seafloor'*'*'5~; (3) by the friction between the penetrating sampler and the sediments 4x'42 (Fig. 5); (4) by the suction of subbottom soft sediments during retrieval of the corer from the subbottom incases of partial initial penetration of the core barrel without complete retraction of the piston prior to pull outS~ and (5) by possible loss of certain bottommost sections during pull up. Careful enginecring of the corer "~2and smooth barrel 32 greatly reduce the friction and enable recovery of longer and less disturbed core samples. The criteria for corer design were defined by Hvorslev 42 as shown in Fig. 6. C~ and Co determine the disturbances caused by friction inside and outside the barrel respectively, and C,, determines the disturbance caused by displacement of sediment' by the penetrating barrel. The larger the diameter of the barrel and the thinner the wall of the barrel, the less disturbed is the core sample. Sampling of coarse sediments fi'om submersible tethered platforms Owing to the incompressibility cohesionless sediments such as densely packed sands, gravels and stiff clays offer high resistance to 'single shot' coring techniques, such as those used to sample fine cohesive sediments. Loosely packed cohcsionless sediments, such as sand and silt, are easily eroded upon sampling, their void ratio drastically decreases, and their internal structure is heavily disturbed by the impact of the penetrating sampler. Fine sands and silts have often liquefiable metastable structures that collapse ifsampling is even slightly forceful. Moreover, the short sediment samples which do enter the sampling barrels are easily washed out during pullup and hauling unless spccial retainers are used, and this causes additional distfirbancc. In an effort to overcome the resistance to sampling offered by these sediments several types of samplers have been developed, which presently are capable of penetrating some 2 to 30 m below seabottom. Yet, none of these samplers is capable of recovering sufficiently

Review of marine geotechnical studies at continental margins(l): G. Ahnagor Two scientific deepsea drilling projects have been successfully carried out--experimental Mohole 59'6~ and the Deep Sea Drilling Project (DSDP) programme 61'62 which uses a specially designed drilling vessel, the Glomar Challenger. The techniques used in drilling and sediment sampling were described and summarized by Noorany 28, McClelland ~6, Tirey sv and Andresen et al. 2s and will not be included in this article. It should be mentioned, however, that the samples recovered are very disturbed, and consequently are hardly adequate for geotechnical testing.

Disturbances caused by change of ambient conditions The stresses acting on naturally-packed sediment particles are anisotropic (i.e., lateral and vertical stresses are not equal), and the retrieval of a sediment sample will inevitably result in changes of these effective stresses, subsequently leading to a decrease in the shear strength of the sediment sample, even if mechanical disturbances are avoided63-67. The transfer of the sediment sample from the sea subbottom to the surface will result in a change of the total stress state on the sample, and in an appreciable increase in ambient temperatures. These lead to the expansion of the pore water, changes in their viscosity, release of dissolved gases and promotion of bacterial activity (which also leads to release of gases), and to subsequent

L DI Ot OW De (~

Figure 5. Disturbance of sample caused by friction between penetrating sampler and sediment. (1) Experimental sampling in varved clay, showing formation of cone-shaped plug of sediment during (A) slow and (B)fast penetration (from Hvorslev and Stetson41): (2) Sediment core in the lower edge of core barrel (from AImagor 53) undisturbed samples adequate for precise geotechnicaI studies. They are, however, of great practical value for engineering purposes such as foundation of underwater structures, underwater mining and dredging. In all, rigid bottom-standing tethered submersible platforms provide a stable base for the drilling and sampling operations, which are monitored from a surface vessel or a platform. Penetration is effected by percussion and hammering, vibration, rotation, oscillation, jetting or any combinations of these. The basic methods of penetration and of sample recovery of these samplers are summarized in Fig. 7. The samplers currently used are described in detail by Welling and Cruickshank 27, Rosfelder s6, Noorany 2s, Tirey s7, and Andresen et al. 25 among others. However, high operational costs, awkward handling on board, shallow penetration, which is usually the case, and insufficient quality of the samples recovered limit their exploitation. The disturbances caused by these apparatus were discussed by Jonasson 5s.

Deep penetration sampling Offshore deep penetration drilling and sampling that are carried out for engineering purposes are mostly linked with foundation investigations of oil drilling platforms.

Parameter

Inside clearance

Dm - De

D,

ratio. C i

Outside clearance ratio. C o

Co

o~ - o.~ Ca

(sharpness), a

M a x i m u m safe cr u n d l s l u r b e d l~ngth, L s

(fO0)

D w - .Dr D'--'--~'~(100)

=

Area r a t i o , C a

Cutter angle

Desired Value of Parameter

Equation

C, -

=

-

De2

Maximum sampling length Inside d=ameter of the b~r~el Outside diameter of the barrel Outside d,ameter of the cutler t nside diameter of the cutter Cutter Ingle Jsharpness)

(I00)

Funchon of Parameter

C i = 0 to 0.5 for very short cores; 0.75 t o 1.5 f o r long corers.

Reduces inside friction.

Co = < 2 o r 3 f o r cohesive sediments.

Controls outside friction.

C m = < 10. if possible, or unless corer provided w i t h stationary piston.

Shows ratio of volume of displaced sediment to volume of sample.

Cr I 0 ~ and po'.,sibly less than ,5~ .

L I = 10 tO 2 0 D s for cohesive soils.

Disturbance by

cutting tip. Additional wall friction effects. Grea'~er sample length w i t h

fixed piston.

Figure 6. Design parameters for core barrel (after ttrorslev 42, and Rosfelder and Marshall 3z)

Applied Ocean Research, 1982, Vol. 4, No. 2

95

Review o f marine tjeoteclmical stttdies at continental margins(l): G. Almagor SAMPLING TOOLS BASIC

METHODS

IMPVLSE PERCUSSIONVIB2ATION

9 ..~.~ ~ . ( . ~ ' . i . P~LEGEQ I BECKER OVERBURDEN w ALPINE ~=~,-,~==

stuo,~

pI

OF PENETRATION

-

20TATION OSClLL/fflON JETTING COMBINATION

~ t~?~,-= L~SC/I,~C

ROTAI~Y COINER

0 S E. ALLUVIALJATLASCOPCO ROCKEATER MINING [OVERBUQDEN DI~ILL '~YDQOP I DI~ILL

_!"1

rATER

c ~ P ~TLTION

I

WITER JF.T$ I

BASIC METHODS OF SAMPLE RECOVERY REPETITIVE BAILING

The basic concepts and techniques of in situ testing were summarized earlier 25'28'73 76 ht situ testing in deep penetration boreholes drilled from platforms, barges or ships is remotely controlled, and in principle is executed much in the same w a y as onshore26.va. 7 7 - 7 9 Remotely controlled, shallow-penetration in sittt testing is carried out by means of tethered platforms and crawlers, and from manned submersibles. T h e y include vane shear device 73'75'78, cone penetrometer 2s'76,v9-at, and density and pore pressure probes 7s. Recently, in situ pore pressure measurements were successfully conducted from a platform tT'sR-ss. I m p a c t penetrometers86_and free fall penetrometers 38'39 are attached to corers. The results of underwater in-place shear strength measurements are c o m p a r a b l e to those obtained by laboratory shear tests conducted on good-quality sediment samples 78"87"88 or differ slightly, especially deeper in the sediment c o l u m n 75'89.

I

CORING

. I w~u~E

REFERENCES 1 2

3 4 Figure 7. Sampling tools-4msic methods o f penetration and o f sample recovery (from Welliny and Cruickshank 27)

5

b r e a k d o w n of the inter-particle b o n d i n g within the sediment sample and re-packing of its particles, which are expressed in further decrease in the shear strength of the sediment sample. If gases are trapped in sittt the disturbances m a y be large as an appreciable expansion of the core sample will occur upon arrival at the surface 6s. Studies made on core samples showed that these disturbances, plus those caused by storage, handling and laboratory treatment of the sediment samples, m a y cause 5 0 - 6 0 ~ ' r e d u c t i o n in shear strength 66"6~. However, if measures are taken to minimize the mechanical disturbances, the reduction in shear strength in the core samples is small. Several methods of quantifying the degree of disturbance were devised 66"69-7t. Sangrey 72 presented methods for predicting the undrained shear strength of marine soils using parameters obtained from tests on disturbed samples. Use of a hyperbaric chamber, in which gas-laden core samples for the Mississippi Delta front are stored and processed under high pressures, has proved to successfully prevent release of dissolved gases and subsequent expansion and disturbance of the samples (Bryant, W. R. personal communication).

6 7 8 9 10 I1 12 13 14 15 16 17

18 IN SITU MEASUREMENTS The large disturbances of the recovered sediment samples have necessitated measurements of the sediment properties. Whereas in situ measurements on land are relatively easily accomplished, in situ measurements at sea are hard to execute and involve highly sophisticated instrumentation and high expenditure.

96

Applied Ocean Research, 1982, Vol. 4, No. 2

19 20 21

Sangrey, D. A. and Garrison, L. E. Submarine landslides, US Geological Surrey Yearbook, 1977, p. 53 Garrison, L. E. Mississippi Delta Project: Instability problems in delta front sediments--a progress report, 1 January, 1974-30 June, 1975, US Geological Survey, Office of Marine Geology, Corpus Christi Office, 33 pp. Nacci, V. A. and Houston, M. T. Structure ofdeep sea clays, Proc. Civil En9. Oeeans-ll, Miami Beach, December 1969, p. 599 Sangrey, D. A. Marine geotechnology--State-of-tfie-art, Marine GeotechnoL 1977, 2, 45 Richards, A. F., Palmer, H. D. and Pcrlow, M. Jr. Review of continental shelf marine geotechnics: distribution of soils, measurement of properties, and environmental hazards, Marine GeotechnoL 1975, 1, (1), 33 Davie,J. R., Fenske, C. W. and Seroeki, S. T. Geotechnical properties of deep continental margin soils, Marine Geotechnol. 1978, 3, (1), 85 Sowers,G. B. and Sowers,G. F. Introductory Soil Mechanics and Foundation, The MacMillan Company, New York, 1961, 386 pp. Pettijohn, F. J. Sedimentary Rocks, Harper and Brothers, New York, 1957, 718 pp. Shepard F. P. Nomenclature based on sand-silt-clay ratios, J. Sediment. Petrol. 1954, 24, (3), 151 Lambe, T. W. Soil Teclmology Summer Session, Massachusens Institute of Technology, 1954 Emery, K. O. The continental sheh'es, Scient. Am. 1968, 221, (3), 106 Griffin,J. J., Windom, M. and Goldberg, E. D. The distribution of clay minerals in the world ocean, Deep-Sea Res. 1968, 15, 433 Friedman, G. M. and Sanders, T. E. Principles of Sedimentology, John Wiley, New York, 1978, 792 pp. Reineck, H. E. and Singh, I. B. Depositional Sedhnentology Environments, Springer-Verlag, Berlin, 1973, 439 pp. Emery,K. O. Relict sediments on continental shelves of the world, Am. Ass. Petrol Geol. B,dL 1968, 52, (3), 445 Emery,K. O., Continental rise and oil potential, Oil Gas J. 1969, 67, (19), 231 Bennett,R. tl, Bryant, W. R. and Keller, G. H. Clay fabric and geoteclmical properties of selected submarine sediment cores from the Mississippi Delta, US Dept. Commerce, NOAA Prof. Paper 9, 1977, 86 pp. Bryant, W. R., Deflanche,A. P. and Trabant, P. K. Consolidation of marine clays and carbonates, Deep-SeaSedhnents, Physical and Mechanical Properties (Ed. lnderbitzen, A. L.), Plenum Press, New York, 1974, p. 209 Terzaghi, K. Varieties ofsubmarine slope failures, Proc.8th Texas Conf Soil Mech. Found. Eng., Bureau Eng. Res. Spec. PubL 29, 1956, 40 pp. Terzaghi, K. and Peck, R. B. Soil Mechanics in Engineering Practice, John Wiley, New York, 1967, 729 pp. Hutchinson, J. N. untitled discussion, Proc. Geotech. Col~ Oslo, 1967, 2, 214

R e v i e w t f marine ~leoteclmical studies ttt continental tnar~,lins(l): G. Altna~lor 22 23 24

25 26 27

28

29 30 31 32

33 34 35 36 37

38 39 40 41 42 43 44

45 46 47

Morgenstern, N. M. Submarine slumping and the initiation of turbidity currents, Marine G~,oteclmique, (Ed. Richards, A. F.), University of Illinois Press, Urbana, 1967, p. 189 Chilingarin, G. V. and Wolf, K. tl. (Eds.), Compaction ofcoarsegrained sediments, Developments in Se,limemology 18A and 18B, Elsevier, Amsterdam, 1975, Vol. I, 552 pp.; 1976, Vol. 2, 806 pp. American Society for Testing and Materials, Underwater Soil Sampling, Testing, and Construction Control, a Symposium presented at the 741h Annual Meeting of the American Society for Testing and Materials, Atlantic City, 27 June-2 July, 1971, Special Techn. Publ. 510, 1972, 241 pp. Andresen, A., Berre, T., Klevcn A. and Lunne, T. Procedures used to obtain soil parameters for foundation engineering in the North Sea, Marine Geotechnol. 1979, 3, (3), 201 McClelland, B. Techniques used in soil sampling at sea, Off~hore, 1972, 32, 51 Welling, C. G. and Cruickshank, M. J. Review of available hardware needed for undersea mining: Exploiting the Ocean, Marine Technol. Soc. Trans. 2rid A. Meet. Cot~ Exhibit, June 1966, p. 79 Noorany, I. Underwater soil sampling and testing - - a state-of-the-art review, in Underwater Soil Sampling, Testing, and Construction Control, a Symposium presented at the 741h Annual Meeting of the American Society for Testing and Materials, Atlantic City, 27 June-2 July, 1971, Spee. Tech. Puhl. 501, 1972, p. 3 Moore, D. G., The free-corer: sediment sampling without wire and winch, Sediment. Petrol. 1961, 31,627 Sachs, P. L. and Raymond, S. O. A new unattached sediment sampler, J. Marine Res. 1965, 23, (I), 44 Hopkins, T. L. A survey of marine bottom samplers, l'ro9. Oceanoy. 1964, 2, 213 Rosfelder, A. M. and Marshall, N. F. Obtaining large, undisturbed, and oriented samples in deep water, in Marine Geotechnique (Ed. Richards, A. F.), University of Illinois Press, Urbana, 1967, p. 243 Silva, A. J., ttollister, C. D., Laine, E. P. and Beverly, B. E. Geotcchnical properties of deep sea sediments: Bermuda Rise, Marine Geotecl, nol. 1976, I, (3), 195 Kullenberg, B. The piston core sampler, Swenka llydroloyieBioloyie Kommissionens Skriften Tredie, Serien Ilydrogrtfi, 1947, I, (2), 46 pp. Andresen, A., Sollie, S. and Richards, A. F. N.G.I. gas-operated sea-floor sample, Proc. 6th Int. Col~ Soil Mech. Foumlation Eny., Momreal, 1965, I, 8 Piggot, C. S. Factors involved in submarine core sampling, Geol. Soc. Am. Bull. 1941, 52, 1513 McCoy, F. W., Jr. An analysis of piston coring through corehead camera photography: Underwater Soil Sampling, Testing, and Construction Control, a Symposium presented at the 741h Annual Meeting of the American Society for Testing and Materials, Atlantic City, 27 June-2 July, 1971, Special ~'chnical Publication 510, 1972, p. 90 Scott, R. E. In-pla.ce soil mechanics measurements, in Marine Geotechnique, (Ed. Richards, A. F.), University of Illinois Press, Urbana, 1967, p. 264 Schmid, W. E. Penetration of objects into the ocean bottom, Proc. Civil Eny. Oeeat,s-ll, Miami Beach, December 1969, p. 167 Emery, K. O. and Dietz, R. S. Gravity coring instrument and mechanics of sediment coring, Geol. Soe. Am. Bull. 194 I, 52, 1685 Hvorslev, M. J. and Stetson, It. C. Free-fall coring tube: a new type of gravity bottom sampler, Geol. Sot'. At,,. Bull. 1946, 57, (10), 935 llvorslev, M. J. Subsurface exploration and sampling of soils for engineering purposes, US Corps of Engineers, Waterways Experimental Station, Technical Report, 1949, 521 pp. Arrhenius, G. Sediment cores from the East Pacific, Rep. Swed. Deep-Sea Exped. 1952, 5, (1), 1 McCoy, F. W. Jr., Von Herzen, R. R., Owen, D. M. and Bontin, P. P. Deep-sea corehead camera photography and piston coring, I|'oods Ilole Oceunoyraphic Institution Reference 69-19, 1969, 68 PP. Richards, A. F. and Parker, !1. W. Surface coring for shear strength measurements, Proe. Ct,~ Ciril Emj. Oceans, San Francisco, September 1967, p. 445 Ross, D. A. and Riedel, W. R. Comparison of upper parts of some piston cores with simultaneously collected open-barrel cores, Deep-Sea Res. 1967, 14, 285 Ricdel, W. R. and Funnel, B. M. Tertiary sediment cores and microfossils from the Pacific Ocean floor, d. Geol. Soc. Station,

48 49

50 51 52 53

54 55 56 57

58 59 60 61 62 63 64 65 66

67 68

69 70 71 72

73

1964, 120, 305 Inderbitzcn, A. L. A study of t he effects of various core san'.plcs on mass physical properties in marine sediments, J. Sediment. Petrol. 1968, 38, 473 Phillips, J. I)., Berggren, W. A., Bertels, A. and Wall, D. Paleomagnetic stratigraphy and micropaleontology of three deep-sea cores from central North Atlantic Ocean, E,trth Phmet. Scient. Lett. 1968, 4, 118 Burns, R. I'. Free-hall behaviour of small, light-weight gravity corers, Marine Geol. 1963, 4, I Kallstenius, T. Mechanical disturbances in clay samples taken with piston samples, R. Swed. Geotech. In.st. Proe. 1958, (16), 75 pp. Jakobson, B. Influence of sampler type and testing method on shear strength ofclay samples, R. Swed. Geotech. Inst. Proe. 1954, 18), 59 pp. Almagor, G. I'hysical properties, consolidation processes and slumping in recent marine sediments in the Mediterranean continental slope of southern Israel: Geolo~jical Survey of Israel Report MG/76/4, 1976, (in ltebrew), 132 pp. Kullenberg, I1. Reports ~f the Swedish Deep Sea Expedition, 1955, 4, 11), 35 Kermabon, A. and Cortis, V. A new "sphincter" corer with a recoiless piston, Marine Geol. 1969, 7, 147 Rosfelder, A. M. Obtaining located samples from sandy and rocky formations in deep water, Proe. llbrhl Dre,19in$! Col~i, New York, 1967, p. 487 Tirey, G. B. Recent trends in underwater soil sampling methods, in Underwater Soil Sampling, Testing, and Construction Control, American Society for Testing and Materials, a Symposium presented at the 74th Annual Meeting, Atlantic City, 27 June-2 July, 1971, Spec. Tech. Puhl. 501, 1972, 241 pp. Jonasson, K. ttaamer vibrocorer and its affect on the geoteehnical properties of cohesive sediments in Gothenburg harbor, Sweden, Marine Gi'oteclmol. 1976, 3, (I), 233 Bascom, W. A llole in the Bottom of the Set:, the Story of the Mohole Project, Doubleday, Garden City, 1961, 352 pp. US National Academy of Sciences, Experimental drilling in deep water at La Jolla and Guadelupe sites, National Research Council Publication 914, 1961, 183 pp. Knapp, R. R. and Larson, V. R. Coring the deep oceans for science, Proc. Civil Emj. Oeeons-II, American Society of Civil Engineers, New York, 1975, pp. 784-800 Demars, K. R. and Nacci, V. A. Significance of Deep Sea Drilling Project sediment physical property data, Marine Geotecl, nol. 1978, 3, (2), 151 Ladd, C. C. and Lambe, T. W. The strength of'undisturbed" clay determined from undrained tests, A S T M Staml. Tech. Publ. 361, 1963, p. 342 Skempton,A. W. and Sowa, V. A.The behavior of saturated clays during sampling and testing, Gbotechnique, 1963, 13, 269 Noorany, I. and Seed, H. B. In situ strength characteristics of soft clays, J. Soil Mech. Foundation Eny. Dir. (ASCE), 1965, 91,(SM2), 49 Noorany, I. and Poormand, i. Y. Effect of sampling on the consolidation of soft clay, Soil Mechanics Res. Rep. Department of Civil Engineering, School of Engineering, San Diego College, 1970, 25 pp. Lee, !1. J. In situ strength of seafloor soil determined from tests on partially disturbed cores, Naval Civil Enyineerin 9 hlboratory, Port lluel,eme, Technical Note N-1295, 1973, 30 pp. Roberts, tl. II., Crastley, D. W. and Whelan, T. Stability of Mississippi River delta sediments as evaluated by analysis of structural features in sediment borings, 8tl, Offshore Tech,ol. Col~, llouston, 1976, 1, 10 Calhoon, M. L. Effect of sample disturbance on the strength of a clay, Am. Sot'. Civil E,y. Trans. 1956, 121, (Paper 2827), 925 Silva, A. J. Marine geomechanics: overview and projections, in Deep-Sea Sedimet,ts, Physical aml Mechanical Properties, (Ed. lnderbitzcn, A. L.), Plenum Press, New York, 1974, p. 45 Schmertman, J. H. The undisturbed behavior of clay, Soil Mech. Found. Dir. (ASCE), 1955, 120, Paper 2775, 1201 Sangrey, D. A. Obtaining strength profiles with depth for marine soil deposits using disturbed samples, in Underwater Soil Sampling, Testing, and Construction Control, American Society for Testing and Materials, a Symposium presented at the 74th Annual Meeting, Atlantic City, 27 June-2 July, 1971, Spec. Tech. Puhl. 501, 1972, p. 106 McDonald, V. J., Olson, R. E., Richards, A. F. and Keller, G. H. Measurements and control system for deep-sea vane-shear

Applied Ocean Research, 1982, Vol. 4, N o . 2

97

Reciew t f marine tleotechnical st,dies at continental marr 74 75

76 77

78

79 80

98

device, Ocean "72, 1972, p. 474 McClelland, B. Trends in marine site investigation: a perspective, I'roc. Offshore Europe Col~, Aberdeen, 1975, Paper OE-75220, 9 PPRichards, A. F., McDonald, J., Olson, R. E. and Keller, G. H. Inplace measurement of deep-sea soil shear strength, in Underwater Soil Sampling, Testing, and Construction Control, American Society for Testing and Materials, a Symposium presented at the 74th Annual Meeting, Atlantic City, 27 June-2 July, 1971, Spec. Tecl,. Publ. 501, 1972, p. 55 de Ruiter, J. The use of in-situ testing for North Sea studies, Proc. Offshore Europe 75 Cot~, Aberdeen, 1975, Paper OE-75219, p. 1 Fenske, C. W. Symposium of In-Place Testing of Soils by the Vane Method: a Symposium presented at the 59th Annual Meeting of the American Society for Testing and Materials, ASTM Spec. Tech. Pubk 193, 1957, p. 16 Doyle, E. tl., McClelland, B. and Ferguson, G. H. Wire-line vane probe for deep penetration measurements of ocean sediment strength, 3rd Offshore Technol. Conf., Dallas, 1972, OTC Paper 1327, p. 121 Eide, O. Marine soil mechanics, application to North Sea offshore structures, Norwegian GeotechnicalIn.~titutePublication 103, 1974, 20 pp. ilirst, T. J., Richards, A. F. and indcrbitzen, A. L. A static cone penetrometer for ocean sediments, Underwater Soil Sampling, Testing, and Construction Control, AST M Spec. Tech. Publ. 501,

Applied Ocean Research, 1982, Vol. 4, No. 2

G. A lmayor 81 82 83 84

85 86 87 88 89

1972, p. 69 Zuidbcrg, tl. M. Seacalf, a submersible cone-lvenetrometer rig, Marine Geotechnol. 1975, 1, (I)," 15 Richards, A. F., Oien, K., Keller, G. I !. and Lai, J. Y. Differential piezometer probe for in silu measurement of seafloor pore pressure, G(otechniqae, 1975, 25, 229 Garrison, L. E. The SEASWAB experiment, Marine Geotechnol. 1977, 2, 117 tlottman, W. E., Suhayda, J. N. and Garrison, L. E. SEASWAB II {Shallow Experiment to Assess Storm Wave Affecting the Bottom), lOth Offshore Technol. Col~, ttouston, OTC Paper 3169, 1978, p. 1059 Tubman, M. Instrumentation of SEASWAB experiment, Marine Geotechnol., 1977, 2, 123 Dayal, V., Allen, J. II. and Jones, J. M. Use of impact penetrometer for evaluation of in-sittt strength of marine sediments, Marine Geotechnol. 1975, 1, (2), 73 Taylor, R. J. and Demars, K. R. Naval in-place seafloor soil test equipment: a performance evaluation, US Natal Civil Engineerin9 Laboratory Technical Note N-1135, 1970, 45 pp. Demars, K. R. and Taylor, R. J. Naval seafloor soil sampling and in-place test equipment: a performance evaluation, US Civil Engineerin9 Laboratory, Technical Report R730, 1971, 59 pp. inderbitzen, A. L., Simpson, F. and Goss, G. A comparison of in sire and laboratory vane shear measurements, Loekhead Missiles and Space Company Report LMSC 681703, 1970, 33 pp.