Three groups of field pull-out comparative tests of soil nails prepared by different grouting techniques were conducted in order to address the issues of difficult control and poor pull-out performance of grouting using traditional grouting technique.The pull-out force and load transfer law of soil nail were examined by traditional grouting technique,improved compaction grouting technique,and step-by-step improved compaction grouting technique(traditional grouting technique first,followed by improved compaction grouting).The results of pull-out force of the field test and the calculation model were compared and analyzed.The results show that the grouting technique significantly affects the pullout force of the soil nail.When the improved compaction grouting technique or the step-by-step improved compaction grouting technique is used,the pull-out force of the soil nail is two times that of the soil nail prepared by the traditional grouting technique,and hardening phenomenon is more obvious in the initial stage of the pullout force.The axial force of the soil nail changes rapidly in the bulb section prepared by the improved compaction grouting technique,demonstrating that the pullout force is mainly contributed by the bulb resistance(75%).The change trend in the back section of axial force of the soil nail prepared by the step-by-step improved compaction technique,is similar to that of the soil nail prepared by the improved compaction grouting technique,whereas it decreases linearly in the front section of the soil nail prepared by the traditional grouting technique.The base force and side friction of the soil nail prepared by the step-by-step improved compaction grouting technique are basically equal,and the pullout displacement at the softening stage is the largest.The side friction of the soil nail prepared by the three grouting techniques is firstly yielded near its top,and the bulb section with larger diameter provides the greatest side friction.The proposed calculation model of pull-out force can well reflect the pull-out law of the soil nail prepared by different grouting techniques in the field application,which provides a theoretical reference for the field application of the soil nail with multiple grout bulbs.
关键词
土钉/注浆工艺/多节泡/土工织物/抗拔力
Key words
soil nail/grouting technique/multiple grout bulbs/geotextile/pullout force
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基金项目
国家自然科学基金资助项目(52008401)
湖南省自然科学基金资助项目(2021JJ40770)
中南大学研究生自主探索创新项目(CX20210266)
中南大学研究生自主探索创新项目(2021zzts0222)
National Natural Science Foundation of China()
Natural Science Foundation of Hunan Province()
Graduate Student Free Exploration Innovation Program of the Central South University()
维普
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