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螺旋锚基础因其能够利用深层土体抗力且具有快速安装和承载的优势而广泛应用于各类岩土工程问题中。多锚片螺旋锚上拔承载特性受埋深、锚片间距、数量、土质条件等因素影响。相邻锚片相互影响导致土体破坏区域重叠,从而影响破坏模式和极限承载力,然而多锚片螺旋锚承载特性的理论及试验研究有限。针对砂土中螺旋锚锚片间距及数量对上拔承载特性及极限上拔承载力影响进行室内1g模型试验研究。结果表明,在中密砂及密砂中,单锚埋深比分别超过6.0和10.5时可认为是深埋锚。中密砂中深埋多片螺旋锚锚片间距在3.0D~4.5D时,各锚片承载能力能够独立发挥,承载量破坏模式发生;密砂中浅埋多片螺旋锚保证承载量破坏模式的锚片间距超过6.0D,但间距为6.0D时,螺旋锚发挥效率超过90%。增加锚片数量可适当提高上拔承载力,但当锚片数量增加使得锚片间距小于某一临界值时,柱状破坏模式发生,螺旋锚承载力不再增加;中密砂中此临界间距约为1.5D,密砂中临界间距约为2.0D。
The screw anchor foundation is widely used in all kinds of geotechnical problems due to its ability to take advantage of deep soil resistance and has the advantages of fast installation and bearing. Multi-anchor screw anchor uplift bearing characteristics by the depth of the anchor sheet spacing, quantity, soil conditions and other factors. The mutual influence of adjacent anchor sheets leads to the overlap of soil failure area, which will affect the failure mode and ultimate bearing capacity. However, the theoretical and experimental studies on the bearing characteristics of multi-anchor screw anchor are limited. In order to investigate the effects of spacing and number of anchor sheets in sand on the uplift and bearing capacity and the ultimate bearing capacity, 1g indoor model tests were conducted. The results show that in the medium sand and sand, the single anchor depth ratio of more than 6.0 and 10.5, respectively, can be considered as a deep anchor. The bearing capacity of each anchor plate can be exerted independently when the distance between the anchor plates with multi-layered helical anchor in the middle sand is between 3.0D and 4.5D, and the failure mode of bearing capacity occurs. The multi-spiral anchor with shallow depth in the sand ensures the bearing capacity failure mode Anchor spacing of more than 6.0D, but the pitch is 6.0D, the helical anchor efficiency of more than 90%. Increasing the number of anchor sheets can improve the bearing capacity of the uplift properly. However, when the number of anchor sheets increases so that the anchor sheet spacing is less than a certain critical value, the columnar failure mode occurs and the screw anchor capacity does not increase any more. 1.5D, the critical spacing in sand is about 2.0D.