城镇搬迁地土壤厚度划分与案例研究

Soil Thickness Partition in Urban Relocation and Case Studies

为确定城镇搬迁地绿化有效土壤厚度,通过对比城镇搬迁地原地土壤和传统农业土壤的差异,基于土壤、杂填土、建筑垃圾和土体等基本概念,对城镇搬迁地土壤厚度进行了定义;基于建筑垃圾层位置和园林绿化种植土相关标准定义了城镇搬迁地绿化有效土壤厚度的内涵;并以上海市世博文化园和三林楔形绿地建成前城镇搬迁地为例进行了土壤厚度划分方法的应用。结果表明:城镇搬迁地土壤厚度是城镇搬迁地内土壤剖面所有的土壤物质层厚度之和;城镇搬迁地绿化有效厚度为在城镇搬迁地中位于地下水之上、自身理化性质符合或者经过改良后符合地方规定的园林绿化种植土标准的土壤物质层厚度。上海市世博文化园建成前城镇搬迁地土壤厚度为2.4~4.5 m,但由于土壤理化性质不符合园林绿化用土标准,绿化有效土厚为零,绿化种植土均需采用客土。三林楔形绿地建成前城镇搬迁地土壤厚度大于1 m,土壤经过改良均可作为园林绿化种植土。但由于地下水层的存在,城镇搬迁地绿化有效土厚为1 m。因此,城镇搬迁地绿化有效土壤厚度划分方法可为城镇搬迁地原地土壤和客土用量的快速估算提供科学依据。

In order to determine the effective soil thickness for the greening of urban relocation sites,soil thickness of urban relocation sites was defined based on the basic concepts of soil,miscellaneous fill,construction waste and soil by comparing the differences between urban relocation and traditional agricultural soils;Based on the depth of the construction waste layer and the relevant standards for landscaping planting soil,the connotation of the effective soil thickness was defined for urban relocation sites,and Shanghai World Expo Cultural Park and Shanghai Sanlin Valley were taken as study examples of urban relocation sites.The results showed that the soil thickness of the urban relocation site is the sum of the thickness of all soil layers in soil profile in the urban relocation site;the effective thickness of the urban relocation site greening is the thickness of soil layer or after improvement which physiochemical properties are in line with the local standards for landscaping planting soil above the groundwater in the urban relocation site.Before the completion of the Shanghai World Expo Cultural Park,the soil thickness of the urban relocation site was 2.4-4.5 m.However,because soil physiochemical properties did not meet the standards of requirements for landscaping use,the effective soil thickness was zero,and extraneous soil had to be used for landscaping use.Before the completion of Shanghai Sanlin Valley,soil thickness of the urban relocation site was greater than 1 m,and soil could be used as landscaping planting soil after improving,but the effective soil thickness for greening was 1 m due to the existence of the groundwater layer.Therefore,the established method in this paper for dividing the effective soil thickness of urban relocation land greening can provide a scientific basis for the rapid estimation of the amount of in-situ soil and guest soil.