Deep compaction of granular soils by Dr. K. Rainer Massarsch

In English only

Deep compaction of granular soils
by Dr K. Rainer Massarsch

Presented at Zhejiang University on January 21, 1999 "International Lecture Series on Geotechnical Engineering and Its Development in the 21st Century" Copyright Zhejiang University, Hangzhou, PR China.

The paper addresses general requirements of compaction of granular soils with respect to design, execution, monitoring and quality control. The advantages and limitations of different field investigation methods are discussed. Methods for deep compaction of granular soils are presented, and their advantages and limitations discussed. A concept describing the compaction mechanism in granular soils is proposed. Finally, the practical importance of the increase of soil strength after compaction, and pre-consolidation effects due to increase of lateral stresses are explained.

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1	INTRODUCTION
1.1	OBJECTIVES OF DEEP COMPACTION
1.2	THE ACTIVE DESIGN CONCEPT
1.3	SOIL PLACEMENT
1.4	OBJECTIVES OF DEEP SOIL COMPACTION

2	SOIL INVESTIGATION METHODS
2.1	STANDARD PENETRATION TEST (SPT)
2.2	CONE PENETRATION TESTS (CPT)
2.3	COMPARISON BETWEEN SPT AND CPT
2.4	PRESSUREMETER TEST (PMT)
2.5	DILATOMETER TEST (DMT)
2.6	SEISMIC TESTS

3	DESIGN ASPECTS OF SOIL COMPACTION
3.1	RELATIVE DENSITY
3.2	SETTLEMENTS ESTIMATES
3.2.1	Tangent modulus approach
3.2.2	Determination of soil modulus from CPT
3.3	SHEAR STRENGTH
3.4	LIQUEFACTION
3.5	COMPACTABILITY OF SOILS

4	DEEP SOIL COMPACTION METHODS
4.1	ENERGY TRANSFER FROM GROUND SURFACE
4.1.1	Dynamic compaction
4.1.2	Impact roller
4.1.3	Vibratory compaction plate
4.2	ENERGY TRANSFER BELOW GROUND SURFACE
4.2.1	Displacement pile method
4.2.2	Vibro-probe and MRC method
4.2.3	MRC compaction system
4.2.4	Vibroflotation
4.2.5	Compaction by explosives

5	HYPOTHESIS FOR COMPACTION MECHANISM IN SAND
5.1	ENERGY TRANSFER FROM SOURCE TO SOIL
5.2	VIBRATION PROPAGATION FROM THE SOURCE TO THE SURROUNDING SOIL
5.3	COMPACTION CRITERIA BASED ON VIBRATION VELOCITY

6	EFFECTS OF COMPACTION ON GEOTECHNICAL PROPERTIES
6.1	CHANGE OF LATERAL EFFECTIVE STRESS
6.2	INCREASE OF SOIL STRENGTH AND STIFFNESS WITH TIME

7	SUMMARY AND CONCLUSIONS

8	REFERENCES