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The difficulties, which are connected with undisturbed sampling, tend to promote direct field tests by which funda-mental soil properties can be ascertained avoiding the im-perfections of sampling.

These tests deserve our fullest attention. Soil, unfortun-ately, is very sensitive to disturbances, which occur even at the most perfect sampling methods known and used so far. I think that during the discussions of this conference we have many times been confronted with this point.

Direct field tests omit a source of difficulties and the use of those tests thcrefore should be strongly promoted.

The tests in use so far and discussed in our Division are various. Of those tests the penetrometer is the most generally used and accepted one. It is used statically and dynamically. The evidence brought forward in the papers and discussions shows that in a number of cases the use of the static penetrometer has led to satisfactory results.

A major point in the discussions has been standardization. It is obvious why and when standardization is necessary. The cone penetration test has not been evaluated, so far, to such an extent that a clearly defined fundamental soil property, such as the angle of internal friction, can be derived from it. The results of the test are given as certain measured values obtained with a certain apparatus.

In that position the valuc of the obtained results consists in the possibility to compare these results for different soils and different circumstanccs and correlate these results with experience and evidence obtained in the field.

This is a sensible opcration, but is sensible only if the test used is strictly standardized.

This holds for any conventional test.

There is no doubt that our attempts for standardization should be carried out with utmost caution. In no event standardization should jeopardize the carrying out of fur-ther research on the subject.

I think I have said enough on this point now. There is an old saying : when everyone shouts for silence there is no silence. Now, if we all discuss the use of standardization there might be no standardization. So let’s have the sub-committee on that subject working in silence and look forward eagerly to the results presentcd by them at the next conference. Thank you.

Le President :

I now ask Mr Tsitovitch if he would present his summary for Section 3A, Shallow Foundations.

SECTION 3 A

M. N. Tsitovitch (U.R.S.S.)

Please, allow me now to say a few words on the discussion in Section 3A.

First of all I would like to express my sincere gratitude to all those who took an active part in the discussion and madę a valuable contribution to it.

In conclusion I should like to stress the following points :

First. We should continue to carry on theoretical and experi-mental research — the latter particularly, on a natural scalę, strictly observing boundary conditions. It is necessary particularly to investigate the strain-stressed State of soils; not only in static condition when their compaction is com-pleted, but also in the course of compaction as well as in the phase of creep and that of progressive flow.

Second. We should welcome the development of engineering calculation methods using the latest computation techniąues for drawing up auxiliary tables.

Third. One should stress the fact of a wider and morę successful practical application of soil mechanics Solutions. Of course, we cannot say that we have madę all the conclus-ions; the analysis of the reports presented to the 5th Conference and by other specialists as well, we believe will be of great benefit.

May I also express my personal satisfaction for the privi-ledge to speak before this high Assembly in such a wonderful country as France whose prominent scientists and engineers (Coulomb, Boussinesą, Caąuot and others) have madę a remarkable contribution to the establishment and deveIop-ment of the science of soil mechanics.

Le President :

We come now to Section 3(B), on Piled Foundations, and I ask Prof. Zeevaert to make his remarks.

SECTION 3 B

M. L. Zeevaert (Mexique)

As your General Reporter in Piled Foundations, Section 3 B, I take the pleasure tó inform you on the events which took place during the Sixth Technical Session.

The panel agreed to concentrate the discussion on the following subjects : (a) Determination of the bearing capac-ity of piles from penetration tests. (b) Piłeś groups. (c) Some aspects of the load capacity of friction piles. (d) Tech-niąue of loading tests and ultimate load definition.

The panel discussed successfully the items proposed, inviting the members to submit morę evidence and contrib-utions on the subjects under discussion.

From panel discussion on point (a), where the ąuestion under discussion was “ Can the ultimate bearing capacity of a deep foundation be deduced from the cone resistance ? ” The panel did not reach dcfinite conclusions, sińce there was disagreement. Ninę members of the Conference discussed this problem but no satisfactory agreement was obtained, as some members reported to have had good agreement and others to have had poor agreement.

Statistical results of this procedurę may present large deviations and caution should be exercised when using these empirical methods. It appears that morę natural scalę tests with different pile diameters are necessary to be able to reach morę definite conclusions. In this linę the IRABA tests were most welcome.

Conceming ąuestion (b) on pile groups, the panel stressed the importance of the behaviour results of one-pile tests to those of smali and of very large groups of piles. The importance of model tests was discussed as a valuable guide to understanding the behaviour of pile groups, as in the case of efficiency because of pile distance. After the panel discussion two members contributed in clarifying some ąuestions raised in the panel discussion. In generał it was agreed that similitude laws between model tests and prototype should be further studied mainly when tests are madę with sand. The remould-ing effects and hardening in clays for the prototype should also be taken into consideration, as these phenomena may affect correlations.

Point (c) was discussed by the panel, and six members of the Conference presented points of vicw on the large possible variation of the “ reduction coefficient ’. Some cases were mentioned where this coefficient is not in agreement with statistical results obtained up to the present. Therefore it appears necessary to classify field pile tests in clay morę carefully to be able to reduce the large deviations encountered in the reduction coefficients ”. These studies had to be madę

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