【作者】 张庆；

【导师】 程赫明；

【作者基本信息】 昆明理工大学 ， 工程力学， 2013， 博士

【摘要】 固化疏浚淤泥-磷石膏混合土是以疏浚淤泥/磷石膏混合物为基质土,通过添加水泥(石灰)将基质土固化为填土材料的一项新技术,以期实现疏浚淤泥、磷石膏两种废弃物的资源化利用。作为一项新型的废弃物资源化处理技术,需要对固化混合土的工程性质进行系统研究,以发展和完善混合料固化处理技术。本文通过无侧限抗压强度试验、直剪试验、固结试验、渗透试验、线性膨胀率检测等一系列室内试验,主要研究了基质土中疏浚淤泥/磷石膏的合理混合比、疏浚淤泥初始含水率、养护龄期、不同固化剂及其掺量等不同因素对固化混合土工程性质的影响；探讨了固化土重塑土工程性质、重塑时机、及其强度折减、恢复机理；初步揭示了膨胀性变化规律及其对固化混合土固化效果的影响,并对固化混合土的膨胀机理进行了分析。固化混合土工程性质研究：(1)影响固化混合土的强度、压缩特性、含水率以及渗透系数的主要因素有：基质土中疏浚淤泥磷石膏混合比、疏浚淤泥初始含水率、养护龄期、固化剂及其掺量。在此基础上提出了固化混合土强度变化与磷石膏掺量的关系模型,该模型把强度随磷石膏掺量的变化分为三个阶段：强度增长阶段；强度降低阶段；强度稳定阶段。(2)相比单一疏浚淤泥固化,固化混合土具有更好的固化效果,可以节省固化剂的掺量；其破坏应变大于单一固化淤泥土,具有较好的韧性和工程适用性。(3)固化疏浚淤泥磷石膏混合土技术是可行的,可以实现同时大量消纳疏浚淤泥、磷石膏两种固体废弃物,且固化成本不高。固化土的重塑特性研究：(1)固化淤泥土、固化混合土的重塑土重塑时强度会发生显著的折减,养护后强度会得到一定程度的恢复。重塑时机是影响强度折减、恢复的最重要因素,其它影响因素还有基质土疏浚淤泥与磷石膏配比、固化剂及其掺量、重塑后养护龄期等。(2)从机理上看,重塑土强度折减主要由于破碎过程对粘聚力的破坏,强度恢复则来源于粘聚力和内摩擦角的增长。固化淤泥重塑土的强度恢复是颗粒摩擦咬合力的增加、凝胶的修复两者共同作用的结果,重塑时机是影响重塑后凝胶修复作用大小的重要因素；而固化混合土重塑土的强度恢复是颗粒摩擦咬合力的增加、凝胶的修复以及胀损三者协同作用的结果,重塑时机是影响三者协调性的重要因素。(3)相比原固化混合土,其重塑土具有更好的压缩特性、更小的渗透系数。(4)重塑土具有较好的工程性质,采用固化土的重塑土作为土方填料是可行的,并分别探讨了固化淤泥土以及固化混合土的最佳重塑时机。固化混合土的膨胀特性研究：(1)固化混合土基本上都具有一定的膨胀性,整体来看膨胀性提高了固化混合土的密实度,对固化混合土是有益的。实验结果表明,线性膨胀率与疏浚淤泥初始含水率、固化剂掺量、疏浚淤泥与磷石膏的配比,养护时间等因素有关,并给出了线性膨胀率随各因素变化规律。(2)机理分析发现,固化混合土水分转化分为三步,水分转化对固化混合土自生体积稳定性,强度影响较大；固化混合土的宏观体积是收缩和膨胀共同作用的结果,宏观强度是膨胀损伤和凝胶修复共同作用的结果。(3)提出了对固化混合土膨胀性设定判断标准,根据前人标准判断,固化混合土的膨胀程度基本上属于微膨胀或中度膨胀,具有较好的工程适用性。更多还原

【Abstract】 It’s a new technology of filling materials use cement (lime) to solidify the mixture of dredged sludge and phosphogypsum. The technology can effectively change two kinds of waste into soil resources. As a new waste treatment technology, it’s valuable to systematic study the properties of solidified mixed soil, in order to develop the technology of treatment mixed-soil.In this paper, A series of laboratory tests has done, such as the unconfined compression test, direct shear test, consolidation test, variable head permeability test and linear expansion ratio test a series of laboratory tests, considering the mixture ratio of the mixed-soil, the moisture content of dredged sludge, curing age, curing agent and dosage. The engineering properties of treated mixed-soil are studied; the remoulded properties of solidified soil are recoveried; the law of expansion of treated mixed-soil is revealed, and the mechanism of treated mixed-soil is analyzed.The researches of the engineering properties of solidified mixed-soil have shown:(1) the strength, compressive properties, moisture content and permeability coefficient of treated mixed-soil are found to be mainly affected by the mixing ratio of dredged sluge and phosphogypsum, the initial moisture content of dredged sluge, curing agent and its dosage, curing age. According to the experimental results, the strength model of treated mixed-soil with phosphogypsum content is established; the strength change is divided into three stages:the strength rising stage, the strength transitional stage, the strength stable stage.(2)The treatment of solidified mixed-soil is better than treated dredged sludge, its strength is far higher, so can save the curing agent. And the failure strain more than single solidified dredged sludge. It shows that the solidified mixed-soil has good toughness and engineering applicability.(3) The technology of solidified the mixed-soil is feasible, which can cheaply treat a great amount of dredged sludge and phosphogypsum at the same time.The researches of the remoulded properties solidified soil have shown:(1) the strength of solidified dredged sludge and solidified mixed soil will be significantly reduced after being remolded, the strength of the remolded solidifiedly soil will be restored to a certain extent after curing. The remolded timing is the most important factor to affect the remoded strength reduction and recovery, and there are some other factors such as the mixing ratio of dredged sluge and phosphogypsum, curing agent and its dosage, curing time.(2) Remolded soil strength reduction is mainly due to the crushing process for the destruction of cohesion; and strength recovery is derived from the increase of cohesion and internal friction. Remolded soil strength of solidified dredged sluge recovery is the interaction effect of the friction bite force increased of particles and the gel repair, the remolded timing is the most important factor to affect the ablitity of the gel repair. But remolded soil strength of solidified mixed-soil recovery is the synergistic effect of the three factors that the friction bite force increased of particles, the interaction of restoration of soil structure and the expansive damage results; the remoded timing of is important factors to affect their coordination.(3) The remolded soil has better better compression characteristics and smaller permeability coefficient comparing to the original solidified mixed-soil.(4)The Remolded soil has better engineering properties, the remolded solidified soil as fill materials is feasible, and the optimum remolded timing of solidfited dredged sludge and solidified mixed-soil is studied.The expansibility and mechanism study shows that the solidified mixed soil has the following characters:(1) solidified mixed soil basically has some swelling, and the swelling increased its strength, which is beneficial to it. Linear expansion is related with the initial moisture content of dredging silt, curing agent content, dredging silt and phosphogypsum ratio, curing time and other factors. The variation patterns of linear expansion under different factors circumstance are given.(2) the mechanism analysis found the hydration conversion process in the solidified mixed soil has three steps, soil moisture conversion has significant impact to the volume stability and strength of solidified mixed soil; the macroscopic volume of solidified mixed soil is the combined action of contraction and expansion, and its macroscopic strength is the combined action of expansion damage and stregth recovery.(3) the criteria of the expansion character of the solidified mixed soil is proposed, based on the relevant information, the solidified mixed soil has small or medium expansion character, and has good engineering applicability.更多还原