말뚝 시공 시 천공요소 기울기 지지력 측정

영신컨설턴트 (02) 529 8803 ystcha@naver.com 2022 4

 

매입말뚝 시공 시 천공심도, 천공기기울기, 천공속도, 회전속도를 측정하여 지지력을 판단 할 수 있습니다.

 

천공 시 시공

 

 

천공 단위 에너지 Energy required to remove a unit volume of rock during drilling

 

e = F/A + 2 π N T/A u.

 

e = Specific Energy (kPa) 천공 단위 에너지

F = downward axial force (kN) 연직력

A = Cross-sectional area of the excavation (m2) 비트 단면적

N = Rotational speed (rpm) 회전수

T = Torque (kN-m) 회전력

u = Penetration rate (m/min) 회전속도

d = Bit diameter (m)(Teale, 1965) 비트 직경

 

천공 단위에너지와 일축압축강도

 

 

천공 단위에너지와 주면마찰력

 

 

Total Specific Energy MWD QA/QC

ISO MWD Specifications

 

ISO standards created for geotechnical purposes in 2016

Specifications for monitoring systems, operations, and data logging

 

MWD Category A - Class 1 monitoring

Max length between sampled measurements is 2.5 cm (Class 1)

Allows indicative interpretation of the strata encountered via compound drilling parameter properties (e.g., specific energy)

Assessment of rock strength and geospatial variability from MWD is a new application with limited work completed

 

 

 

심도측정기 friction wheel	wire에 부착	회전축에 부착

 

측정요소

 

- Date 일시

- Start and stop times for each hole 천공 시작과 종료

- Side and Inclination angle per hole 천공각도 x y

- Drill time per hole 천공 시간

- Drill length per hole 천공 길이

- Average rate of penetration per hole 천공속도

- Events with date and time, registered manually by the user per shift 입력

- User ID

- Date and time for shift start and shift end 작업시간

- Total number of drilled holes per shift

- Total drill length per shift 전체 천공 길이

- Average rate of penetration per shift 평균 천공속도

- Total drill time per shift 전체 천공시간

 

 

말뚝의 연직도 허용 기준

Code	Allowable Tolerance 허용기준
ACI-336	4% of diameter or 75mm; whichever less
BS EN 1536	100mm; for pile diameter(D) ≤ 1000mm 0.1D for 1000<D≤1500 150mm D>1500 Design for rake less than 1 in 15 limit to 20mm/m Design with rake of between 1 in 4 and 1 in 15 limit to 40mm/m
CP4	75mm
BS 8004	Not more than 1 in 75 from the vertical or 75mm Deviation of up to 1 in 25 permitted for bored piles drilled at rakes of up to 1 in 4

Description	Tolerances
	Land Piles	Marine Piles
Deviation from specified position in plan, measured at cut-off level	75mm (15mm for mini-piles)	150mm
Deviation from vertical	1 in 75, 1 in 100 for mini-piles	1 in 25
Deviation of raking piles from specified batter	1 in 25
Deviation from specified cut-off level	25mm