Bentonite Swelling test [GDS CRS cell (상단 배수, 하단 비배수 간극수압측정)]

Bentonite Swelling test

GDS CRS cell (상단 배수, 하단 비배수 간극수압측정)

 

1. 건조 bentonite 설치

- sample ring 높이가 20mm이므로 시료높이는 17mm정도까지 설치한다. swelling 시 높이증가를 고려함.

2. 포화

- Water chamber pressure를 back pressure보다 크게 한다.

- Back pressure는 간극수압측정(시료하단)관으로 물을 공급하여 포화.

- 간극수압측정을 위해 Back pressure 밸브는 잠근다.

-  : 포화도

-  : 간극 수압증가량

-  : 로드셀 하중증가량

-  : (외부 로드셀 하중 – ram 면적 x chamber pressure ) / 시료면적

- 상단 비배수조건

- 상단 비배수

- 상단 비배수용 DISK 국내 제작

3. 온도 증가에 따른 swelling 압력측정

- chamber pressure 고정

- CRS 시험에서 velocity control: 한바믜속도 제로 (0) 입력 .

시험 종료조건 설정 화면 (복수선택 가능)

4. 종료조건

• Maximum Effective Axial Stress

The user may enter a maximum limit for the Effective Axial Stress at which point the test will stop.

 

• Minimum Effective Axial Stress

The user may enter a minimum limit for the Effective Axial Stress at which point the test will stop (more commonly used when unloading a specimen).

 

• Maximum Axial Stress – 2/3 u

The user may enter a maximum limit for the Axial Stress – 2/3 pore water pressure at which point the test will stop.

 

• Minimum Axial Stress – 2/3 u

The user may enter a minimum limit for the Axial Stress – 2/3 pore water pressure at which point the test will stop.

 

• Set Displacement to Zero

If the specimen has just been docked, checking the ‘set displacement to zero’ will set a software zero on the displacement transducer. This is generally onLY done when the specimen has first been docked – i.e the first time the specimen comes in contact with the ram.

 

• Pore Air/Rotation

If this option is selected, when pressing next it will show another screen giving control of pore air pressure and rotational displacement. Note, specialised hardware is required for this testing. (See section 6.3.11)

 

The test settings may be reviewed using the Back button.

Finally, Click Add to Test List to add the newly created stage to the test plan.

5. 온도를 증가시키고  (로드셀 하중), (간극수압증가) 를 측정한다.

Temperature Control System (Heating only) for use with PT100 type temperature sensors: Climate controlled version (Ambient to +100°C).

The climate control system comprises of:

- Direct on cell heating elements and cascade RS232 programmable controller.

- Forced cooling system is not included, cooling is by convection only.

- Allows up to 4 PT100 transducers to be connected to the control unit., typically 1 internal control source and 3 heater pad monitors.

 

20MPa Consolidation Cell with enviromental upgrade (Heating only)

High Pressure Consolidation Cell 20MPa/50mm for use in a GDS Load Frame.

Special back pressure consolidation cell 50mm diameter x 20mm high sample.

- Load applied mechanically via load frame.

- Maximum Strain 100%

- Maximum Pressure 20MPa

Supplied with:

1 off 50mm sample ring, 20mm high.

1 off 50mm sample top cap.

1 off 50mm sintered bronze porous disc.

1 off 50mm cutting ring.

20MPa Consolidation Cell with enviromental upgrade (Heating only)

High Pressure Consolidation Cell 20MPa/50mm for use in a GDS Load Frame.

Special back pressure consolidation cell 50mm diameter x 20mm high sample.

- Load applied mechanically via load frame.

- Maximum Strain 100%

- Maximum Pressure 20MPa

Supplied with:

1 off 50mm sample ring, 20mm high.

1 off 50mm sample top cap.

1 off 50mm sintered bronze porous disc.

1 off 50mm cutting ring.