DILATOMETER TEST

Question 1

The flat plate dilatometer test (DMT) accessories essetially consists of a flat plate measuring _______ mm length X _____ mm width X ____ mm thickness.

Answer 1

220, 95, 14

Question 2

In Dilatometer test, a thin, flat, circular, EXPANDABLE steel membrane having a diameter of ____ mm is located flush at the center on one side of the plate.

Answer 2

60

Question 3

Dilatometer test is particularly useful for _______, _______, and ________ and provides parameters for settlement analysis, bearing capacity, and soil stiffness.

Answer 3

clays, silts, sands

Question 4

The dilatometer probe is inserted into the ground with a cone ______________ testing rig.

Answer 4

penetrometer

Question 5

In dilatometer testing, ____ and ______ lines extend from the surface control box, through the penetrometer rod, and into the blade.

Answer 5

gas, electric

Question 6

In dilatometer testing, at the required depth, high pressure _____________ is used to inflate the membrane.

Answer 6

nitrogen

Question 7

At dilatometer test, at the required depth, two pressure readings are taken which are

Answer 7

The pressure A required to “lift off” the membrane

The pressure B at which the membrane expands 1.1 mm into the surrounding soil

Question 8

A dilatometer test is normally conducted at depths _________ to _________ mm apart.

Answer 8

200 , 300

Question 9

The A and B readings are corrected as follows by Schmertmann, 1986

Answer 9

Contact stress, po = 1.05(A+delta A - Zm) - 0.05 (B- delta B -Zm)

Expansion stress, p1 = B - delta B - Zm

delta A = vacuum pressure required to keep the membrane in contact with its seating

delta B = air pressre required inside the membrance to deflect it outward to a center expansion of 1.1 mm

Zm = gauge pressure deviation from zero when vented to atmospheric pressure

Question 10

The result of a given test is used to determine three parameters:

Material Index , ID =

Horizontal stress index, KD =

Dilatometer modulus , Ed (kN/m^2) =

Answer 10

ID = (p1 - po) / (po -uo)

KD = (po - uo)/O’o

Ed = 34.7 ( p1 - po)

uo = porewater pressure

Question 11

Figure 3.35 shows the results of a dilatometer test conducted in Bangkok soft clay and reported by Shibuya and Hanh (2001). Based on his initial tests, Marchetti (1980) provided the following correlations:

Ko =

OCR =

Cu/O’o = for normally consolidated clay

Cu/O’o = for overly consolidated clay

Es =

Answer 11

Ko = (KD/1.5)^0.47 - 0.6

OCR = (0.5 KD)^1.56

Cu/O’o = 0.22 - - - Nc

Cu/O’o = 0.22 * (0.5 KD)^1.25 - - - Oc

Es = (1 - us^2) ED

Ko = coefficient of at rest earth pressure

Question 12

Other relevant correlations using the results of dilatometer tests are as follows:

Cu =

drained friction angle =

ultimat drained friction angle =

Answer 12

Cu = 0.35 O’o ( 0.47 KD) ^1.14

Drained friction angle = 31 + KD/ (0.236 + 0.066 KD)

Ultimate Drained Friction Angle = 28 + 14.6 log KD - 2.1 (log KD)^2