Lab Report JKR Probe Test

LECTURER’S NAME: DR. MAZIDAH MUKRI PROGRAMME CODE: EC220 (2C1) SUBJECT: GEOTECHNICAL LABORATORY EXPERIMENT: JKR PROBE TEST

GROUP MEMBERS: 1. 2. 3. 4.

MUHAMMAD DANIEL BIN MOHD SHAH MUHAMMAD NAJMUDDEEN BIN NIZAR MUHAMMAD SYAHIR BIN HAMIDON AIN SYAFIQAH FIRZA BINTI ABDUL JALIL

(2016209142) (2016209158) (2016209224) (2016209218)

INTRODUCTION JKR Probe Test is a dynamic penetrometer test used to check the consistency of the subsoil. Mackintosh Probe which is has 30 °

cone penetrometer while JKR probe has 60 °

cone

penetrometer. This is a light dynamic test and the cone is driven directly into the soil by driving a hammer 5kg. Weight dropping through a free height of 280mm. The probe is unable to penetrate into medium strength soil and gravelly ground.

THEORETICAL BACKGROUND The JKR Probe is a lightweight and portable penetrometer. It is considerably faster and cheaper tool than boring equipment especially when the depth of exploration is moderate and the soils under investigation are soft or loose. The rods consist of 16mm diameter High Yield Steel each of length approximately 120cm. Then the rods are connected to each other by 25mm outer diameter couplings. Coupling will provide the lateral supports to the rods to prevent buckling during driving the rods. Driving is performed with a small hammer of 5kg and falling vertically through a fixed height of 30cm along a guide a rod. The total number of blows required for the pointer to penetrate a distance of 30cm is recorded and used as a measure of the consistency of cohesive soil and the packing of granular soil. The advantages of using this JKR Probe test is light and easy user, does not need skill worker, economical, provides a disturbed soil sample for moisture content determination, faster and cheaper tools.

OBJECTIVE 1. 2. 3. 4. 5.

To determine the coefficient of permeability of soil To determine the sub-surface stratigraphy and identify materials present To estimate geotechnical parameters To determine soil classification To determine allowable bearing capacity of the ground using JKR dynamic cone penetrometer

APPARATUS 1. 2. 3. 4. 5.

JKR probe set with additional rods and coupling Scale Chalk Datum bar Lifting tool

PROCEDURE 1. Equipment for the test was assembled. 2. The rods and hammer was joined using the rod coupling. Grease has sweep up for an easy dissembles later. 3. Distance of 0.3m was measured and marked on the rod start from the tip of the cone. 4. The equipment was set up on the ground. 5. The hammer is pulled until reached the maximum and the hammer was dropped freely to driven the cone into the soils. 6. The sum of the number of blows for penetration of 0.3m was recorded in the data sheet. 7. The hammer is taken off on the last 0.3m of each rod and joined the existing rod with another rod. 8. The blow will stopped when the blow count is more than 400 for 0.3m penetration or achieved the desired depth. 9. Step 6 to 8 was repeated until the 3rd rod was driven into the soil. 10. After the 3rd rod was successfully driven into the soil, the rod was pulled using the lifting tool. 11. The equipment was dissembled and cleaned before storing.