【作者】 罗小勇；

【导师】 詹良通； 陈云敏；

【作者基本信息】 浙江大学 ， 岩土工程， 2012， 硕士

【摘要】 垃圾填埋场内污泥简易填埋所形成的污泥库已经严重影响了填埋场正常运行,不仅减少了填埋库区的库容,还增加了填埋场的稳定安全隐患。随着垃圾产量的增加,造成填埋场库容日趋紧张,需对填埋场中的污泥库进行加固处置,以便在其上方填埋垃圾,恢复库容。污泥库的加固处置和填埋库容的恢复是我国目前许多垃圾填埋场亟需解决的难题。目前关于污泥库中降解污泥工程特性及加固处置的研究尚属空白。本文针对成都固体废弃物填埋场污泥库的加固处置和二期库容恢复这一工程问题,对处置库污泥的工程特性进行测试研究,评估其对垃圾堆体稳定性的影响,最后提出污泥库污泥的加固处置方法。本文的主要工程及研究成果如下：(1)对污泥库中的污泥进行钻孔取样、静力触探、十字板剪切试验等岩土工程勘察与测试,结果表明：污泥库中降解污泥可分为硬塑层、流态层及软塑层；与常规淤泥相比,污泥的强度更低,其侧摩阻力、锥尖阻力和不排水抗剪峰值强度仅为10-1～101kPa量级,且强度随深度的增加而增加；(2)对不同深度污泥试样进行室内土工试验,结果表明：污泥为一种高有机质含量、高含水率、高液塑性、高压缩性、低密度、低比重、低渗透性、低固结系数、低抗剪强度的有机质土；含水率、有机质含量、渗透系数随着填埋深度的增加而减小,密度、比重随着填埋深度的增加而增加；污泥的压缩固结为典型的非线性固结特性；抗剪强度随竖向压力的增加亦为非线性；(3)污泥真空预压模型试验结果表明：真空度在污泥中传递困难,真空度沿塑料排水板衰减,径向方向传递距离有限；常规真空预压加固处理污泥固结沉降缓慢,改进后的增压式真空预压的固结沉降及强度增长效果明显好于传统真空预压,并将抗剪强度实测值与计算值进行对比分析,得到污泥库强度增长计算的合理抗剪强度指标；(4)根据Hansbo计算方法和非线性固结度计算方法的计算结果与模型试验测试结果的对比分析,提出利用非线性固结计算方法分析污泥库固结沉降和强度增长,得到污泥库在不同真空压力下、排水板间距、预压时间等工况下的固结沉降值和强度值；(5)利用GEO-Slope软件分析污泥库对垃圾堆体稳定性的影响,结果表明：在未加固处理的污泥坑上堆填垃圾会引发堆体管涌滑移失稳,本工程污泥库由于库底防渗衬垫系统薄弱界面的存在,即使污泥库加固处理强度足够,上覆堆体仍然会沿污泥库底滑移失稳,需对污泥库上覆堆体进行降水和坡形优化,并得出坡形优化后污泥加固处理的强度要求；(6)根据污泥真空预压模型试验后所测得的抗剪强度,污泥库污泥固结沉降后的强度增长计算值以及污泥库上覆堆体稳定性所需加固处理的强度,建议采用真空预压联合堆载预压对污泥库进行加固处置。更多还原

【Abstract】 The operation of many landfills has been seriously influenced by the sludge reservoir simply trenched in the landfill which reduces storage capacity of the landfill and will trigger waste mass instability. As the disposal of MSW, increases available storage of landfill is limited. Nowadays different treatment measures are undertaken in many landfills to assure subsequent disposal on the sludge reservoir. The predecessors have mainly researched into the geotechnical characteristics of fresh sludge and ultra-soft soil reinforcement disposal The improvement of the sludge in the reservoir and storage restoration is an unsolved problem by which many landfills in China are confronted, In this paper, for solving the problems of reinforcement disposal of sludge reservoir and restoring the capacity of Phase II project in Chengdu MSW landfill, the geotechnical properties of the sewage sludge taken from the disoposal site were measured, then the its influence on slope stability of MSW landfill were evaluated. Finally, the reinforce disposal methods of sludge reservoir was proposed.The major studies and achievements in this thesis are as following:(1)A thorough geotechnical investigation consisted of borehole sampling, laboratory tests, cone penetration tests and vane shear tests were conducted to get the engineering properties of sludge in the reservoir, the result showed that: the sludge could form hard crust layer, fluid layer and fluid plastic layer with different geotechnical characteristic, to place in the sludge reservoir for a considerable period. The sludge had much lower strength than the muddy soil. The sleeve friction, tip resistance and shear strength was of the order 10-1-101kPa, as well showed an increasing trend with depth.(2)The geotechnical test was conducted on the sewage sludge with different depth, the study founded that: the sewage sludge with biodegradation was an organic soil with the characteristic of high values in organic content, water content, plasticity index, compressibility as well as the low values in permeability, consolidation coefficient and shear strength. The organic content and water content of sludge in the sludge reservoir showed a decreasing trend with the depth; specific gravity and density showed an increasing trend with depth. The consolidation of the sewage sludge showed a non-linear behavior.(3)A conventional and air-boosted vacuum-preloading model tests were conducted to explore the consolidation settlement, strength improvement of degraded sewage sludge with vacuum preloading technique and its feasibility.(4)Experiments results of large-scale model tests were compared with that of conventional consolidation theory and non-linear consolidation theory, and a new design method suitable for sewage sludge was proposed, which was applied to subsequent analysis of consolidation settlement and strength improvement of sludge in Chengdu landfill reservoir.(5)The software Geo-Slope was made used to analyze the second phase design plan of storage capacity restoration of Chengdu landfill, and two optimized design schemes on waste mass slope angle and corresponding controlling measures on stability were obtained, based on which required undrained shear strength of sludge after treatment was proposed.(6)According to gain in undrained shear strength of sludge in model tests and required strength to assure slope stability of second phase storage restoration project, the method of vacuum preloading combined with surcharge load on sludge reservoir was proposed.更多还原