experimental results, it is demonstrated that the theory can explain the consolidation cheracteristlcs of aged cl~ys. Cce~ariso~ with results from consolidation tests in the laboratory have shown that the reliability of the method is ~ti~actery. 82207~ S ~ T N G SHALE AND COLLAPSING SOIL Ruckw~n, A C; Barrett, R K Transp Res Rec, NT~0, 1981, P~I-45 Reviews 2 major causes of distc~tion of h ~ m ~ V pavements in Colorado: swelling shale amd collapeimg soil. Occurrence, sampling and testing methods, add methods of cc~rection amd l~evention of these phenomena are discussed. Low-level blasting is l~'esented as one method of l~eventiDg or eC~recting sw~11~ng shale problems. Both swelling shales a~d collapsing soils are regarded as prodUCtS of local geologic, ge~n~phic and climatic factors.
822075 DEVELOPMENT OF A LABORATORY C(IMPACTION-DNGRADATION TEST F(~q SHALES Hale, B C; Lovell, C W; Wood, L E Transp Res Rec, N~O, 1981, P~5-52 Noudurable shales used in embankments must be thoroughly broken down during compaction and placed as soll fill. The develo~nent of a stardard testing procedure in order to compare compaction-degradation behaviour of shales in the laboratory with their b e h a v l o t w in the construction l~ocess is described. After testing 3 different I~diana shales it was concl~led that impact anl static ccmpection tests were suitable for a s t a D d a r d teat, b u t that the impact test w~s likely to be mc~e widely
accepted. 822076 SOIL-SUCTION A ~ O A C H S'w'~r.T.TNG POTENTIAL
Dynamic properties 822078 INFLUENCE OF S~EAR VELOCITY ON THE FRICTIONAL RESISTANCE OF ROCK DISCONTINUITIES Crawfc~d, A M; Curran, J H Int J Rock Mech Min Sci, VI8, N6, Dec 1981,
~o5-515 A study has been made into the nature of the rate-depeddent behavlour of rock Joints. An experimental investigation usiug a dy~AmlC direct shear machine showed the frictional resistance af rock Joints to be depeudent on the rate of shear displacement ar~ that the magnitude of this effect was quite variable, depending mainly on the rock type add normal stress level. In general, for harder rocks, the frictional resistarce was found to decrease with increasing shear displacement rates greater than a variable critical velocity. Conversely, for softer rocks, the resistance was observed to increase with increasing shear velocity, up to a critical shear displacement rate, add thereafter remain essentially constant. Auth. 822079 RECIPROCAL CHARACTER OF RAYLEIGH-WAVES AND CRACKS Rossmanith, H P; Fourney, W L Rock Mech, VI4, N1, May 1981, ~ 7 - 4 2 Utilising dyr~m~c photoelasticity a dual creekelastic wave problem is investigated: the initiation of cracks by s u l ~ r l m p o s i n g Rayleighwaves ani the generation of Rayleigh-waves dtwing non-statior~ry crack movement. Auth. 822080 M0~UEUS AND DAMPING OF ASPHALTIC C O N ~ USING THE RESONANT COEU~N. TECHNICAL NOI~ Allen, D L; Deen, R C Geotech Test J, V3, N~, Dec 1980, P167-171
FOR EVALUATION OF
Mou, C H; Chu, T Y Transp Res Rec, N790, 1981, P~-60 It is suggested that usiug soil suction as a ma~or variable in the evaluation of swelling potential, rather than using water content as the only variable to re~esent chaDges in soll moisture, would be advantageous. An experiment to directly determine soil suction for an expansive clay is described. A laboratory swell-testing progran~e was then carried out to determine a ~ benefits from including soil suction as a variable in investigations of all factors influencing the swelling of clays. These factors included method of c ~ o n ~ initial dry density add initial water content. It was concluded that it was very useful to include soil suction as a variable.
822oTT V O L ~
CHANGES IN COMPACTED CLAYS AND SHALES ON SA~'JRATION Abeyesekera, R A; Lovell, C W Transp Res Rec, VT~O, 1981, P67-73
Discusses the volmne-chs~e characteristics of 2 fill materials: a ~ plastic clay add a medium-har~, noddurable shale, both from IrzLiama, USA. Statistically derived prediction equations are given in terms of: (1) compacted density (void ratio), (2) water comtent, amd (3) eor~ining pressure for fully sattu~t~d samples. The equations show how voltmae ehaDges o n saturation can be e s t i ~ f ~ d and used in the d e s i g n l~hase to control t h e effects of c ~ , ~ e s s i o n add swelli~g in an earth fill.
Repc~ts the application of the Drnevich lor~tudimal-tarsiomal resonant colmnn to the Youmgs modulus of asphaltic concrete. Two problems occurrimg were the loss of coupling between the test specimen add the apparatus add the failure to effectively reduce spurious machine vibrations at high frequencies. 822081 DYNAMIC PROPERTIES OF SOME COHESIVE SOILS OF ONTARIO Kim, T C; Novak, M Can Gsotech J, V18, N3, Aug 1981, P371-389 Results from lab investigations into the dyr~m~c behaviour of soils are presented. A resonant c o l ~ apparatus was used to study s e v e n different undisturbed soils (silty clays add cls~ey silts). The v~riatlons of t h e d ~ c s h e a r modulus and dampir~ ratio with void ratio, confining pressure, strain add stress history were studied. The information obtained could then be used in the analysis add d e s i g n c~ foundations and structures exposed to dyr~mlc loads.
822082 RESONANT COLUMN TECHNIQUE FOR DYNAMIC TESTING OF COHESIVE SOILS. TECHNICAL NOTE Novak, M; Mira, T C Can Geoteeh J, VI8, N3, Aug 1981, I~-II.55 A resonant colmnn apparatus was modified to facilitate d ~ m l c testimg of cohesive soils. TO alleviate difficulties caused by air penetration into the confining medium and sample, a =,wll telescopic ple~iglass cell is placed in the main large cell. In this in~er cell, mercury is used as a substitute confining medium far long term and high pressure tests. The testing procedure for cohesive soils is described.