Development of penetration rate prediction model using shield TBM excavation data

쉴드 TBM 현장 굴진데이터를 이용한 굴착속도 예측모델 개발

Abstract

Mechanized tunneling methods, including shield TBM, have been increasingly used for tunnel construction because of their relatively low vibration and noise levels as well as low risk of rock-falling accidents. In the excavation using the shield TBM, it is important to design penetration rate appropriately. In present study, both subsurface investigation data and shield TBM excavation data, produced for and during ${\bigcirc}{\bigcirc}{\sim}{\bigcirc}{\bigcirc}$ high-speed railway construction, were analyzed and used to compare with shield TBM penetration rates calculated using existing penetrating rate prediction models proposed by several foreign researchers. The correlation between thrust force per disk cutter and uniaxial compressive strength was also examined and, based on the correlation analysis, a simple prediction model for penetration rate was derived. The prediction results using the existing prediction models showed approximately error rates of 50~500%, whereas the results from the simple model proposed from this study showed an error rate of 15% in average. It may be said, therefore, that the proposed model has higher applicability for shield TBM construction in similar ground conditions.

최근 국내 터널공사에서 낙반사고의 위험성이 낮고 진동과 소음이 적은 쉴드 TBM을 이용한 기계화 터널공법이 많이 적용되는 추세이며, 이러한 쉴드 TBM으로 터널 굴착 시 적절한 굴착속도를 설계하는 것이 무엇보다 중요하다. 본 연구에서는 ${\bigcirc}{\bigcirc}{\sim}{\bigcirc}{\bigcirc}$ 고속철도 쉴드 TBM 공사구간에 대하여 지반조사 결과와 TBM 굴진데이터를 분석하고 이를 기존 연구자들에 의해 제안된 경험적 굴착속도 예측방법에 적용하였다. 또한, 현장 굴진데이터 중 커터 당 추력과 지반 일축압축강도와의 상관관계를 분석하고 이를 통해 TBM 터널 설계 시 커터 당 추력과 일축압축강도를 변수로 굴착속도를 예측할 수 있는 간편 모델을 도출하였다. 기존 해외의 여러 굴착속도 예측 모델들을 해당 TBM 현장에 적용한 결과 예측치와 측정된 굴착속도는 약 50~500%의 비교적 큰 오차를 보인 반면, 본 연구에서 도출된 굴착속도 예측모델은 평균 약 15%의 오차율을 나타내어 추후 유사한 지반조건을 가진 쉴드 TBM 현장에 대해서 적용성이 높을 수 있을 것으로 기대한다.

Fig. 1. Chart of NTNU model factor (example)

Fig. 2. Structure of shield TBM

Fig. 3. Configuration of shield TBM cutter head

Fig. 4. Ground conditions and boring locations (○○~○○ high-speed railroad ground survey report)

Fig. 5. Thrust depending on excavation distance

Fig. 6. Torque depending on excavation distance

Fig. 7. RPM depending on excavation distance

Fig. 8. Penetration rate depending on excavation distance

Fig. 9. Penetration rate depending on thrust and torque

Fig. 10. Prediction of penetration rate (only uniaxial compressive strength & thrust)

Fig. 11. Prediction of penetration rate

Fig. 12. Results of regression

Fig. 13. Prediction of penetration rate (using proposed equation)

Table 1. Major specifications of shield TBM