摘要
珠江口西岸地区软土极为发育,地面沉降灾害尤为严重。查明区域软土的分布规律、工程地质特性和地面沉降灾害分布特征对地区工程建设和防灾减灾具有重要的现实意义。本文从古地理及沉积环境角度对软土的成因进行分析,并结合钻探等手段探究研究区软土平面及纵向分布规律。在此基础上,基于InSar反演和地面调查等方法揭露软土地面沉降灾害现状。分析结果显示:(1)珠江口西岸地区由于独特的地质、地理成因而形成明显的区域性,使得区内软土成为全国“最软”的软土,具有承载力低、受荷后变形大、时间效应明显、与建筑物共同作用能力强等特性。(2)区内软土从三角洲腹地到沿海、从丘陵、台地到平原,软土厚度总体呈增大趋势。垂向上大体分为全新世一层和更新世一层两层软土,两层软土的厚度差异较大,从空间分布上看,全新世软土广泛分布在滨海平原区,而更新世软土分布仅在局部有分布;从三维上的分布特征看,全新世软土在空间上具有连续性,大部分地区两层软土在垂向上不具备连续性,一般由砂层或者粘土层隔开。更新世软土与基岩面不直接接触,但是在局部地区全新世软土与基岩面直接接触。(3)利用卫星雷达遥感技术和短基线集法(SBAS)反演成果看,研究区内毗邻石岐河的工业园区为沉降严重发育的区域,沿石岐河呈环状空间分布特征,沉降速率最大可达40mm/y,工业园区内沉降特征明显;在全区范围内共发现302个沉降点(地段),收集地面沉降点(地段)148个,其中浅基础的居民楼、厂房、广场等为地面沉降易发性区域,区内道路多处于沉降状态。研究结果为软土地面沉降灾害的防治提供重要的基础数据。
The soft soil on the west bank of the Pearl River Estuary is extremely developed,and the land subsidence disas⁃ter is particularly serious.Finding out the distribution law of regional soft soil,engineering geological characteristics and the distribution characteristics of land subsidence disasters has important practical significance for regional engineering construction and disaster prevention and mitigation.This paper analyzes the genesis of soft soil from the perspective of paleogeography and sedimentary environment,and explores the horizontal and vertical distribution of soft soil in the study area combined with drill⁃ing and other methods.On this basis,based on InSar inversion and ground survey methods,the status quo of subsidence dis⁃asters on soft ground is revealed.The analysis results show that:(1)The region on the west bank of the Pearl River Estuary has a distinct regionality due to its unique geology and geography,making the soft soil in the region the"softest"soft soil in the country,with low bearing capacity and large deformation after loading.,The time effect is obvious,and the ability to in⁃teract with the building is strong.(2)The thickness of soft soil in the region is increasing from the hinterland of the delta to the coast,from hills,platforms to plains.The vertical direction is roughly divided into the first layer of Holocene and the first layer of Pleistocene soft soil.The thickness of the two layers of soft soil is quite different.From the spatial distribution point of view,the soft soil of Holocene is widely distributed in coastal plain area,while soft soil of Pleistocene is widely distributed in coastal plain area.The soil distribution is only distributed locally;from the three-dimensional distribution characteristics,the Holocene soft soil has spatial continuity.In most areas,the two layers of soft soil do not have continuity in the vertical direc⁃tion,and are generally separated by a layer of sand or clay.The Pleistocene soft soil is not in direct contact with the bedrock surf
作者
胡飞跃
邓成坚
HU Fei-yue;DENG Cheng-jian(Guangdong Provincial Geological Survey Institute,Guangzhou 510080,China)
出处
《地下水》
2021年第6期189-193,共5页
Ground water
基金
粤港澳湾区1︰5万环境地质调查(平沙农场幅、荷包岛幅、平岚幅鳌头圩幅)项目
广州多要素城市地质调查项目(DD20190291)。
关键词
软土
地面沉降
分布规律
沉降灾害
INSAR
Soft soil
land subsidence
distribution law
subsidence disaster
InSAR
