【作者】 张艳；

【导师】 冯秀丽；

【作者基本信息】 中国海洋大学 ， 地质工程， 2013， 硕士

【摘要】 青岛北客站工程选址为老填海垃圾填埋场，对老垃圾填埋场占地重新利用、进行地下工程建设，在国内尚属首例，国际上也不多见。其地下基坑开挖部分地层环境包括2~3m的建筑垃圾和5~12m的生活垃圾，实践证明在垃圾土环境中进行地下工程建设存在诸多的问题。本文在总结了垃圾土地层中基坑设计与开挖阶段特点的基础上，分析问题存在的原因，并提出了相关解决措施，主要研究内容包括以下四个部分：（1）填埋场垃圾土物理力学性质试验：借鉴国内外研究垃圾土物理力学性质的试验方法，采用试验手段测试该填埋场4m、8m、12m垃圾土层物理力学性质，并结合现场实测数据，给出该填埋场中垃圾土的抗剪强度指标建议值；（2）垃圾土钻孔灌注桩成桩塌孔扩径原因分析与解决措施：在垃圾土物理力学性质试验的基础上，采用数值模型试验的方法，对钻孔灌注桩塌孔问题成因进行了讨论，同时，结合现场的资料调查和整理，总结了造成垃圾土孔壁塌孔的主要原因，并提出了合理的施工措施；（3）垃圾土地层土压力时空变化特点研究：结合现场土压力实测数据，分析了垃圾土土压力时空变化，即垃圾土环境中基坑开挖支护过程中的围护结构的受力变化，同时，结合工程中三种围护结构形式，分析了在垃圾土层开挖过程中作用在三种不同围护结构上的土压力分布特点，并探讨了垃圾土的开挖特性；（4）基于实测数据的垃圾土中围护结构受力变形特点和垃圾土开挖特性研究：结合现场变形与应力实测数据，从围护结构变形、支撑轴力、地表变形规律入手，分析垃圾土中围护结构变形特点与土体变形特点，并比较了三种围护结构条件下的实测数据。并结合数值分析软件，对柔性支撑体系、双排桩两种不同支护形式下的垃圾土层开挖过程中的变形进行了数值计算分析，重点研究垃圾土层开挖过程中的基坑变形，给出了合理计算模型及垃圾土开挖参数；随着经济的发展，用地日益紧张，老垃圾填埋场改建工程势必会越来越多的出现，同时，为更合理利用空间，地下工程建设更是如火如荼的发展，本文以工程实测为研究依托，研究了垃圾填埋场中深基坑工程建设中存在的问题与难点，为今后类似垃圾填埋场的岩土工程建设提供参考。更多还原

【Abstract】 Qingdao North Station is located in the reclamation area of landfill. As a researchobject, the station had been monitored thoroughly during construction. The stratumfrom top to bottom is construction solid waste, municipal solid waste, argillaceoussilty clay, silty clay, rhyolite, argillaceous sandstone, tuff, etc. Solid waste layers is4~12m. The main structure of this station is constructed by open-cut method.The mainresearch includes four parts as followed:(1) Landfill garbage soil physical and mechanical properties testing: research athome and abroad for reference, the physical and mechanical properties of garbage soiltest method, test by test means the4m,8m,12m garbage landfill site soil physicaland mechanical properties, and connecting with the field measured data, given thelandfill garbage soil shearing strength index in the suggested value;(2) During the construction of the bored piles method, it found that the holecollapse become serious, it will not only affect the quality and the speed of pile, butalso cause serious waste of cement, so the garbage soil hole wall stability is a problemurgently to be solved. Bored piles based on the investigation and study of theengineering hole and the hole diameter of pile collapse phenomenon, from theengineering properties of garbage soil, leachate and waste soil layer thickness andconstruction machinery, such as factor analysis of the mechanism and reason of thesephenomena, and puts forward corresponding preventive measures, to providereference for similar engineering;(3) A mechanical behavior of solid waste during foundation pit excavation isdiscussed on the base of the in-situ monitoring results of earth pressure and fieldmeasured data in solid waste. During excavation, the soil strength increases, which ismostly because of the variances of characteristics of soil in unloading state.Measurement of earth pressure is less than computation, and the value graduallydecreases during excavation. In the end, it tends to be stable or slightly higher than theminimum. Compared with soft soil, the change is not only related to the deformationbut also the change of soil property, especially, the influence of fiber to the shearstrength of solid waste. By analyzing changing characteristics of earth pressure in solid waste, from the surface of earth within0m~5m, experience value of lateral earthpressure coefficient is0.35during excavation and0.25after excavation, and within5m~10m, the value is0.55during excavation and0.45after excavation.Theconclusions will provide the reference for future similar projects;(4) Based on the measured data of garbage soil retaining structure deformationcharacteristic and the waste soil excavation characteristics research: combined withfield measured data, the deformation and stress in retaining structure deformation,supporting axial force and the surface deformation law, this paper analysis thegarbage soil retaining structure deformation characteristics of soil and the deformationcharacteristics, and compare the three kinds of palisade structure under the conditionof the measured data. Combining numerical analysis software, the flexible supportingsystem, double row piles under the two different support forms of garbage in theprocess of soil excavation deformation are analyzed in numerical calculation, keyresearch garbage in the process of soil excavation deformation, gives a rationalcalculation model and the waste soil excavation parameters.In recent years, urban land is expanding to the surrounding areas, some oldlandfill site is planning for construction. Lacking of data about foundation pitexcavation in old landfill site, the collection of in-situ monitoring data is verynecessary. Monitoring the earth pressure on retaining structure in the solid wasteduring excavation. Combined with the engineering properties test results and the fielddata, engineering properties of solid waste during excavation could be analyzed,which will provide the reference for future similar projects.更多还原