평판재하시험을 이용한 공동 복구재료의 지지특성에 관한 현장실험

A Field Test on Bearing Capacity Characteristics of Materials for Ground Cavity Restoration Based on Plate Bearing Test

Abstract

본 연구에서는 하수관 손상 등과 같은 원인에 의해 발생한 공동을 개착식으로 복구하기 위하여 개발된 복구재료를 이용하여 평판재하시험 기반의 현장실험을 실시하였다. 또한 실험결과를 이용하여 복구재료에 대한 지지력을 비교하였으며, 하중지지특성을 분석하였다. 시험 결과, 팽창매트를 지표로부터 각각 0.1m, 0.2m 하부에 매설한 경우에 원지반의 최대 응력조건에서의 지지효과는 약 66%~70% 정도인 것으로 분석되었지만, 매설깊이에 따른 지지효과의 차이는 크지 않은 것으로 나타났다. 콘크리트매트가 적용된 경우의 지지효과는 원지반에 비하여 약 82%~90%로 나타났으며, 팽창매트로 보강된 경우에 비해서도 약 50% 정도의 지지효과를 보였다. 그리고 복구재료에 따른 허용지지력을 분석한 결과, 팽창매트와 콘크리트매트가 매설된 경우의 허용지지력은 원지반 대비 각각 약 130%~150%와 약 160% 이상을 확보하는 것으로 분석되었다.

This paper described a results of field test based on plate bearing test of the restoration material, which was developed to restore the ground cavity due to sewerage damage. The analysis of bearing capacity characteristics on the restoration materials was performed by experimental results. The results showed that the load bearing capacity in the maximum stress condition of the foundation ground is about 66%-70%, when the expansion mat is embedded at the bottom of 0.1 m and 0.2 m from the ground surface. However, The load bearing capacity of expansion mat according to embedded depth was not large. The load bearing capacity of concrete mats was about 82%-90% compared with that of ground surface, and it showed about 50% of the load bearing capacity compared with the expansion mat. As a result of analysis of allowable bearing capacity according to restoration materials, it was confirmed that the allowable bearing capacity of the expansion mat and the concrete was about 130%-150% and about 160% more than the foundation ground, respectively.

Fig. 1. Field tests site

Fig. 2. Test results for engineering properties of soil

Fig. 3. Materials for ground cavity restoration

Fig. 4. Field tests details

Fig. 5. Plate bearing test cases & installation depth of restoration materials from ground surface

Fig. 6. Procedure of field tests

Fig. 7. Test results of foundation ground

Fig. 8. Test results of ground applied in expansion mat - directly on the ground surface

Fig. 9. Test results of ground applied in expansion mat - G.L. -0.1m

Fig. 10. Test results of ground applied in expansion mat - G.L. -0.2m

Fig. 11. Test results of ground applied in concrete mat - directly on the ground surface

Fig. 12. Test results of ground applied in concrete mat - G.L. -0.1m

Fig. 13. Test results of ground applied in concrete mat - G.L. -0.2m

Fig. 14. Comparison of stress-settlement curve according to restoration materials

Fig. 15. Comparison of allowable bearing capacity according to restoration materials

Table 1. Summary of soil properties

Table 2. Allowable bearing capacity of ground according to restoration materials