dmt (flat dilatometer test)

CIE 409 기초공학 1

DMT (Flat Dilatometer Test)

A Flat Dilatometer probe consists in a steel blade with a circular membrane in one of its sides. The membrane has electrical sensors which can detect its position (flexed to the inside or outside and parallel to the blade).This blade is pushed into the ground and at desired depths the membrane is inflated using any kind of compressed gas, normally nitrogen.When the probe is pushed into the ground the soil pressure makes the membrane flex to the inside of the dilatometer blade. At measurement depths the membrane is inflated and an "A" reading of pressure is obtained when the membrane reaches its initial position (parallel to the blade), and a "B" reading is obtained when the membrane displaces 1.1 mm to the outside.This parameters are used in several correlations to obtain properties of the soil, such as compressibility and soil behavior classification.


DMT (flat Dilatometer Test)딜라토미터시험

-원형멤브레인을가스압력으로수평방향으로수축과팽창시켜, 이때팽창과수축변위에서의압력으로부터지반의특성을추정하는실험

1

2

3

1.05( ) 0.05( )p A A B Bp B Bp C A


DMT (flat Dilatometer Test)

1

2

3

1.05( ) 0.05( )p A A B Bp B Bp C A

D

2 12

D

1'

0

D

2 1

1

(dilatometer modulus, E )

34.7( )1

(lateral stress index, K )

(material or deposit index, I )

sD

Dv

D

EE p p

p uK

p pIp u

딜라토미터 계수

수평응력지수

지반지수


PMT (Pressuremeter Test)

http://www.ce.gatech.edu/~geosys/Faculty/Mayne/Research/index.html


Field vane shear test, FVST

2

6

110 2 3

(

uTsK

D H DKH

비배수전단강도

여기서 D는베인의지름cm), H는베인의높이(cm)

현장베인시험

-연약하고포화된점성토지반의비배수전단강도를추정하기위해실시하는현장시험


Undrained shear strength (su) measurement Field Vane

su(mob) = su(FV)

Correction factor to account for:1. Direction of shearing2. Time to failure3. Disturbance4. Progressive failure


Seismic Reflection Test

CIE 409 기초공학 8Lecture 3. Subsoil Exploration 8

Seismic Refraction Test

Vertical GeophonesSource(Plate)

Rock: Vp2

Soil: Vp1

oscilloscope

x1x2x3x4

t1t2t3t4

Note: Vp1 < Vp2

zR

Determine depthto rock layer, zR



Crosshole TestingOscilloscope

PVC-cased Borehole

PVC-cased Borehole

DownholeHammer(Source) Velocity

Transducer(GeophoneReceiver)

t

x

Shear Wave Velocity:Vs = x/t

TestDepth

ASTM D 4428

Pump

packer

Note: Verticality of casingmust be established by

slope inclinometers to correctdistances x with depth.

SlopeInclinometer

SlopeInclinometer


Downhole TestingOscilloscope

Cased Borehole

TestDepth

Interval

HorizontalVelocity

Transducers(GeophoneReceivers)

packer

PumpHorizontal Plank

with normal load

Shear Wave Velocity:Vs = R/t

z1z2

t

R12 = z12 + x2

R22 = z22 + x2

x

Hammer




SASW, MASW


Boring Log

dmt (flat dilatometer test)

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