DHARMCOMPACTION OF SOIL 447(ii) By way of neat sketches explain (a) the effect of moisture content on the dry density for a
constant compactive effort, (b) effect of compactive effort, on the γd-moisture content rela-
tionship.
(iii) Write a brief note on ‘Proctor’s needle.
(iv) Write a brief note on the ‘compaction in the field’ bringing out the various types of rollers and
their effectiveness with respect to different soil types.
(v) Write critical notes on AASHO Compaction test. (S.V.U.—Four-year B.Tech. OCt., 1982)
12.5 Write brief notes on ‘compaction’ and ‘consolidation’ of soils differentiating the two.
(S.V.U.—B.E. Part-time—Dec., 1981)
B.E., (R.R.)—Nov., 1969.
B.E., (N.R.)—Sep., 1961.
12.6 Listing the various factors that influence the compaction of soils, show their influence with
illustrative sketches of compaction curves. (S.V.U.—B.E., (R.R.)—Sept., 1978)
12.7 What is the significance of compaction of soils? Describe how quality control is ensured in con-
structing an earth embankment.
(S.V.U.—B.E., (R.R.)—Dec., 1971, June, 1972, Nov., 1972—Nov., 1975)
12.8 Draw a curve showing the relation between dry density and moisture content for Standard Proc-
tor test and indicate the salient features of the curve. Explain why soils are compacted when (i)
preparing a subgrade and (ii) constructing an embankment. Describe how quality control is
maintained in a rolled fill dam. (S.V.U.—B.E., (R.R.)—May, 1975)
12.9 Explain why soils are compacted in the field. How is the degree of compaction ensured in the
field (i.e., control of field compaction)? Distinguish between ‘compaction’ and ‘consolidation’ of
soils. Bring out the effects of (i) moisture, (ii) compactive effort and (iii) soil type on the compaction
characteristics of soils. Illustrate the answer with typical ‘moisture-dry density’ plots.
(S.V.U.—B.E., (R.R.)—Nov., 1973)
12.10 Describe the Proctor “Compaction Test” and give its for construction of earth embankments.
(S.V.U.—B.E., (R.R.)—Nov., 1969)
12.11 Define “Optimum moisture content of a soil” and state on what factors it depends.
(S.V.U.—B.E., (R.R.)—Dec., 1968)
12.12 (a) What are the laws governing compaction of (i) cohesionless soils like sand and (ii) moder-
ately cohesive soils like sandy clay?
(b) To what compaction pressure does the Standard Proctor Test correspond? Indicate how the
standard proctor test can be modified to suit the compacting machinery actually used at site
for the efficient compaction of embankment. (S.V.U.—B.E., (R.R.)—Sept., 1968)
12.13 The maximum dry density and optimum moisture content of a soil from standard proctor’s test
are 18 kN/m^3 and 16% respectively. Compute the degree of saturation of the sample, assuming
the specific gravity of soil grains as 2.70. (S.V.U.—B.E., (R.R.)—Nov., 1973)
12.14 The wet weight of a sample is missing in a Proctor test. The oven-dry weight of this sample is
189 N. The volume of the mould used is 1000 cm^3. If the degree of saturation of this sample is
90%, determine its water content and bulk density.
12.15 a soil in the borrow pit has a water content of 11.7% and the dry density of 16.65 kN/m^3. If 2,070
m^3 of soil is excavated from it and compacted in an embankment at a porosity of 0.33, calculate
the compacted volume of the bankment that can be constructed out of this volume of soil.
12.16 The soil from a borrow pit is at a bulk density of 17.10 kN/m^3 and a water content of 12.6%. It is
desired to construct an embankment with a compacted unit weight of 19.62 kN/m^3 at a water
content of 18%.