SUMMARY

The objective of the investigation presented here were twofold. One was to explain a new technique for shear-wave detection in soil, the other was to review and study selected measurements of the velocity of P and S- waves in different areas, and to discuss the relationship between V p (and V s ) and blow count from satndart Penetration test (SPT) and Cone Penetration Test (CTP). See figs. 11, 12, 13. Both the P- and S-wave velocity data in sediments (sand, silt and clays) included 75 selected in-situ measurements at depths to 200 meters. Energy was released within 0.5m. of the ground surface and was initiated along the hypothenuse of the cone (see figs.7,9) by either a charge of dynamite weighing between 0.5 and 1 kg, or by a 50 kg cone- shaped weight dropped from a height of 1.5m. See figs.5,6 and 9a.

i)  Relations between S-wave velocity in ground and N value of SPT (and CPT) have been given by Imai, Sakai and Kanai as:

V s = 92.1 N 0.329 , IMAI et al. (SPT)

V s = a . N 0.5 SAKAI- (CPT) See (fig. 10a,b)

V s = 19 N 0.6 KANAI SPT

ii) The upper bound of P and S wave velocities as a function of number of blows have been established and emprical relationship was determined. See figs. (11, 12, 13)

V s = a N 0.418 ,Izmir –SPT –Kuran

V p = a N 0.48 ,Izmir – SPT – Kuran

V p = a N 0.458 , (Ankara – METU) – CPT – Kuran

V p = a N 0.205 , Sapanca, Izmir, and Egridir – SPT – Kuran

V p = a N 1.33 , Samsun Airport Landslide Area – SPT – Kuran

iii) The relationship between V p ( or V s ) and N is not lineer, and the result shown that consistent velocity steps occur within the range in which the soil describes as “Dense”. See figs.11,12.

It is belived that the observed P-wave velocity steps as a result of increase in saturation of the alluvial material.

But the cause of S-wave velocity steps occurring in the V s versus N plot is still not known.

See fig.11.

iv) The resistivity values of clay (CL), silt (ML), silty clay etc., are between 5-30 meters. See fig.14.

As a result, it is not possible distinguish the clay from silt duruing the course of geoelectrical field studies.

However, the plastic clay (CH), can be distinguished from the silty clay by their characteristic “G”(shear modulus) versus “µ” (poisson ratio) plot (see fig.15). As the rigdity modulus of soils reprresented by such a line increases, the poisson ratio (µ) decreases.

If the geophysical engineer knows the (µ) and (G) for a given soil, he can predict the type of soil without having any bore hole data.

v) Extensive seimic-microzonning studies were carried-out in Turkey by using Professor Medvedev's technique. These data were obtained from Sapanca, Izmir, Foça, Samsun Airport Lanslide Area, and Lanslide Area of Egridir (see figs. 17, 18, 19, 20 and 21)

The plot of seismic-intensity- increase, “n” was found to be higher in value especially in the active landslide area. This experimentally observerd fact may explain why some of the landslide occurrence are closely associated with the earthquakes.

ÖZ

 

Bilindigi gibi granüler zeminler üzerinde kesme veya S-dalgasinin elde edilmesinde en büyük güçlügü bu dalganin sahada etkin sekilde yaratilmasi teskil etmektedir. Diger taraftan S-dalgasinin yayilimi sirasinda zeminde meydana gelen deformasyon nedeniyle enerji kaybi önemli olmaktadir. Bu nedenle kesme dalgasi mesafenin artmasi halinde çok büyük sönüm göstermekte ve kayitlar üzerinde belirgin bir sekilde elde edilmesi zorlasmaktadir. Asagidaki arastirmalardan esas gaye iki gurup altinda toplanabilir.

•  S-kesme dalgasinin 200 metre derinlige kadar etkili bir sekilde elde edilmesi için gelistirilmis yeni bir yöntem sunulmasi..

•  Bu dalganin elde edilmesini takiben asagidaki mühendislik problemlerin çözümünde nasil uygulanacaginin incelenmesidir.Bunlar sirasiyla:

SPT (Standart Penetrasyon Test) sonuçlariyla kesme veya S-dalgasi ve P-dalgasi hizlariyla iliskilerinin arastirilmasi ve zeminlerin YUMUSAK- SERT arasindaki yerlerinin bulunmasi.

Deprem bölgelerinde yapimi öngörülen köprü, üst geçit v.s. gibi mühendislik yapilarin oturacagi zeminlerin (T pp ) hakim titresim periyotlarinin hesaplanmasi.

Dinamik poisson orani “µ” hesaplanmasi ve arazideki G max - µ ve arasindaki iliskilerin saptanmasi .

Titresim yapan aletlerin oturacagi zeminlerde elastisite modülü Ed'nin saptanmasi.

Heyelan sahalarinda yamaç asagi etkili olan kayma modülü G max degerinin bulunmasi olacaktir.

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