文章摘要

文章信息/Info

Title:: Analysis on Spatial Distribution Feature of Softsoil in Guangzhou Urban Region and its Seismic Subsidence Based on Dense Drillling Holes

Author(s):: BI Lisi; CHEN Xiaofang; MA Haoming; LU Banghua; (Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology,Guangdong Earthquake Agency,Guangzhou 510070,Guangdong,China)

Keywords:: Guangzhou urban region; drillling hole; softsoil; earthquake; seismic subsidence

摘要:: 以面积为270 km²的广州城区为研究区,利用高密度分布的近12 000个钻孔,判别出广州城区的软土层,详细分析了其空间分布特征。结果表明:广州城区内的软土主要为淤泥、淤泥质土,大部分地段为单层,埋藏深度小于6.0 m,且中部较浅,南北两侧较深。软土的沉积厚度较大,并呈现出研究区南部、西部的厚度大,中部、北部的厚度小,靠近河流岸边的厚度大,远离河流的厚度小的特点,同时还存在2个沉积中心。在强烈地震时广州城区内相当一部分面积可能产生软土震陷,软土震陷区主要集中在研究区的西部和南部。由于软土的厚度与埋深、液性指标和孔隙比等指标不同,震陷性在空间上呈现出轻微、中等、严重等不同危害程度。

Abstract:: Taking Guangzhou urban region with an area of 270 km² as the study area,using about 12 000 drillling holes with a high density,we identified the softsoil layer,and analyzed its spatial distribution characteristics in detail. The results show that:The softsoil in Guangzhou urban is mainly composed of silt and muddy soil. Most of sections are single-layer,buried less than 6.0 m,and it is shallower in the middle and deeper in both sides of the north and south. The softsoil layer is rather thick,which shows thicker in the south and the west,thinner in the middle and the north,and thicker near the river,thinner far away from the river. Meanwhile,there exits two deposition centers where the softsoil layer is very thick. Besides,an evaluation of softsoil seismic subsidence in the Guangzhou urban region was made,and the result shows that the seismic subsidence of softsoil may happen in the west and the south of the study region when the strong earthquake occurred. And it will damage slightly,medium,or seriously in different zone because of the different thickness,buried depth,liquid index and void ratio of softsoil.