ISSN 2096-4498
CN 44-1745/U
Tunnel Construction ›› 2018, Vol. 38 ›› Issue (6): 1014-1021.DOI: 10.3973/j.issn.2096-4498.2018.06.018
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WEI Qingcen1, ZHANG Junru2, *, HE Jixiang3
Received:
Revised:
Online:
Published:
Abstract:
The width and depth of the foundation pit of Zhangcha Station on Foshan Metro Line No. 2 are 50.3 m and 16.9 m respectively. Part of the pit is located under the existing Chanxi Road Bridge with clear height of 7 m. In order to solve the problems of support of superwide deep foundation pit in low space, pile foundation underpinning of existing viaduct, etc., a series of technical measures are proposed, as follows. (1) Pile foundation underpinning of highrise pile cap technology is used to underpin the bridge pile in the middle station, and the underpinning cap is higher than the surface of station pit; the inner support of the foundation pit passes through the existing and new pile foundation to form a symmetrical support; and the inner support is relatively independent of the existing and new piles. (2) The width of the diaphragm wall is adjusted to 4 m; and the small drilling rig is used to cut the groove to improve the construction technology under the bridge. (3) The measures of increasing the anticollapse hole between the diaphragm wall and the existing piles on both sides is proposed. (4) The inner support of foundation pit adopts concrete support and temporary columns to increase the stability of inner support. The measures adopted have solved the mutual influence of underpinning system and foundation pit, which can ensure the safety of superwide and deep foundation pit in low space and the safety of the existing pile foundation. The numerical calculation and field construction indicate that the key underpinning technology for pile foundation of existing viaduct in superwide and deep foundation pit is rational, safe and feasible.
Key words: metro station, low space, superwide deep foundation pit, existing viaduct, pile foundation underpinning of highrise pile cap
CLC Number:
U 45
WEI Qingcen, ZHANG Junru, HE Jixiang. Key Underpinning Technology for Pile Foundation of Existing Viaduct Beam in Superwide Deep Foundation Pit of Metro Station[J]. Tunnel Construction, 2018, 38(6): 1014-1021.
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URL: http://www.suidaojs.com/EN/10.3973/j.issn.2096-4498.2018.06.018
http://www.suidaojs.com/EN/Y2018/V38/I6/1014