论文总字数：44543字

摘 要

随着我国工业化、城市化的迅猛发展，高污染工厂搬迁遗留下大量污染土地资源有待再开发利用，其业已成为当前我国环境岩土领域务须解决的重大问题。重金属污染土传统水泥基材料固化稳定化技术存在固化体碱性高、耐久性能不佳、不利于二次开发利用等诸多缺点。本文通过优化材料和配比研发了新型固化剂磷酸钙水泥（CPC），并以甘肃白银某铅锌冶炼厂Pb、Zn、Cd复合污染白银土为研究对象，开展了CPC固化稳定化重金属复合污染土的相关试验研究。通过多组理化特性、无侧限抗压强度、TCLP浸出等室内试验，深入研究了多种配比下的CPC固化稳定化Pb、Zn、Cd复合污染土的效果，并开展了多种固化剂固化污染土的综合对比研究。研究结果表明，CPC材料具有固化稳定化效果好、酸碱度中性、固化体强度高、药剂成本低等诸多优点。本文主要的研究工作有：

1.深入研究了多种配比CPC及SS-B、SS-C固化土的物理、化学特性。分析了不同掺量及龄期下CPC固化污染土的含水率、密度、酸碱度、电导率，并同SS-C、SS-B固化剂进行了对比。研究结果显示，随着龄期和掺量的增加，固化土含水率逐渐减小，干密度逐渐增大， CPC固化土pH值显著低于传统水泥及SS-B、SS-C固化剂,各固化剂中以CPC固化土的EC值最低，其中2:1配比的最低，表明CPC材料固化土酸碱度适中的同时能有效固定土壤中盐分，能够满足种植土对土壤pH值和EC的要求。

2.通过TCLP浸出试验，深入研究了不同掺量下CPC固化污染土的环境安全特性。对不同掺量多组配比CPC及SS-C、SS-B材料固化土的TCLP浸出液重金属浓度、酸碱度和电导率进行了分析。研究结果表明： CPC等固化剂均能有效降低土中重金属的浸出浓度，其具体效果因重金属种类和固化剂类型不同而异，且掺量越高、龄期越长其处理效果越好。同掺量下，CPC及SS-B材料固化稳定重金属能力显著高于SS-C ，其中CPC固化Zn能力略低于SS-B，但其对Pb、Cd的处理效果与SS-B相当。而浸出液pH值结果表明CPC固化土具有较SS-B及SS-C固化土更佳的酸缓冲能力。

3.基于无侧限抗压强度试验，探讨了多种固化剂固化污染土强度及应力应变特性。分析研究了掺量、龄期、CPC配比、固化剂类型对固化污染土强度、应力应变曲线、破坏应变及变形模量的影响。研究结果表明随着龄期和掺量的增加，固化土强度呈上升趋势，脆性提高，且CPC固化土的强度显著高于SS-B、SS-C材料固化土，其中尤以3:1及2:1配比下的CPC固化土强度较高，表明使用CPC固化剂固化稳定化重金属污染土能够更好的满足工程建设对地基强度的要求。

4、通过层次分析法系统对比分析了多种CPC配比及SS-B、SS-C处理重金属污染土的技术经济及环境效益。研究结果表明，综合考虑环境安全性、pH值、成本、CO2排放量、能耗及强度六大关键指标，3:1配比的CPC固化剂相较于其他种类固化剂技术、社会、环境效益突出，能在最大程度上满足重金属污染土固化稳定化及再利用对于固化剂各项指标参数的要求

关键词：磷酸钙水泥、固化稳定化、pH值、TCLP浸出试验、无侧限抗压强度、层次分析法

Abstract

With the rapid development of China's industrialization and urbanization, high polluting factories move left a large number of land resources pollution to be further development and utilization, what has become the major problems in China's environmental geotechnical field must be solved. Heavy metal contaminated soil traditional cement based material solidification technology has many advantages, such as high alkalinity, poor durability, and hard to be recycled. In this paper, by optimizing the ratio and material we developed a new type binder of calcium phosphate cement (CPC), and studied in Pb, Zn, Cd compound pollution soil as the research object. We carried out a experimental study of CPC stabilized heavy metal composite contaminated soil. Through the indoor experiments such as multi - physical and chemical properties, unconfined compressive strength and TCLP, we studied the effect of CPC curing Pb, Zn and Cd composite contaminated soil, and carried out a comprehensive comparison of curing pollution soil with various binders . The results show that CPC material has many advantages, such as good curing effect, pH value, high curing strength, low cost of pharmacy, etc.. The main work of this paper is:

1. Study the physical and chemical characteristics r of solidified soil solidified by SS-B, SS-C and CPC of three ratio. Analysis the cement contaminated soil water ratio, density, pH, conductivity of the different content and age, and compared the CPC with SS-C and SS-B binder. The results show that with the increase of age and the amount of binder, the moisture content of solidified soil gradually decreases and the dry density increases gradually. The CPC binder’s pH of solidified soil was significantly lower than that of the conventional cement and SS-B, SS-C binder. The EC value of CPC was the lowest of each binder, and the lowest has a ratio of 2:1. It is indicated that the salt content of CPC binder can be fixed effectively while the binder has a Moderate pH, and the requirement of pH and EC of the soil can be satisfied..

2. The environmental safety of solidified contaminated soil under different dosage of CPC was studied by the leaching experiment of TCLP. Analyzed the concentrations of heavy metals contain the pH, and electrical conductivity of leaching solution of TCLP, CPC,SS-B and SS-C. The results show that the leaching concentrations of heavy metals in soil can be effectively reduced by CPC and the other binders. The effect of the kind of heavy metal and the type of binder is different, and the higher the amount, the better the treatment effect is. With the same amount of SS-B and CPC, the ability of stable heavy metals was significantly higher than that of SS-C, and the CPC’s ability of solidificating Zn was slightly lower than that of SS-B, but the treatment effect of Pb Cd was equivalent to SS-B. The pH of the leaching solution showed that the CPC solidified soil had a better capacity of acid buffer than the SS-B and SS-C solidificating soil..

3. Based on unconfined compressive strength test, the strength and stress-strain characteristics of various binders for solidificating soil were studied.We also studied the effects of the amount of mixture, age, CPC ratio and kind of binder on the strength, stress-strain curve, failure strain and deformation modulus of the cured soil .The results of the study show that with the increase of age and dosage, the strength of the solidified soil showed a rising trend, brittleness is increased and the strength of the cement soil was significantly higher than that of SS-B, SS-C material is solidified soil, especially to 3:1 and 2:1 ratio of the solidificating soil’s strength is much higher.So the use of CPC binder for the stabilization of heavy metal contaminated soil can better meet the requirements of engineering construction for foundation strength.

4. Through the analytic hierarchy process, the technology economy and environmental benefit of heavy metal contaminated soil by CPC and SS-B and SS-C were compared and analyzed. The results show that considering the six key indicators of environmental safety, pH, cost, CO2 emissions, energy consumption and intensity, 3:1 ratio of CPC binder compared to other types of curing agent technology, social and environmental benefit is outstanding, to the maximum extent meet the heavy metal contaminated soil solidification / stabilization and reuse for curing agent parameters

Keywords: calcium phosphate cement, solidification / stabilization, pH, TCLP leaching test, unconfined compressive strength, analytic hierarchy process

目录

摘 要 I

Abstract III

第一章：绪论 1

1.1 研究背景及研究意义 1

1.2 重金属污染场地固化稳定化技术国内外研究现状 2

1.2.1 重金属污染场地修复 2

1.2.2 固化稳定化技术 3

1.2.3 水泥固化稳定化（S/S）技术 4

1.3 磷酸钙水泥及其固化稳定化重金属机理分析 5

1.3.1磷酸钙水泥材料概况 5

1.3.2磷酸钙水泥的水化机理 6

1.3.3磷酸钙水泥的固化稳定化机理分析 8

1.3.4新型磷酸钙水泥固化稳定化重金属污染土的优点 8

1.4本文研究内容及技术路线 9

1.4.1研究内容 9

1.4.2技术路线 10

第二章：试验内容及试验方法 11

2.1试验材料 11

2.1.1 污染土的基本特性 11

2.1.2 固化剂材料 12

2.2试验方案 13

2.3试验方法及试验步骤 13

2.3.1 试验土样的制备 13

2.3.2 无侧限抗压强度试验 15

2.3.3 物理化学特性试验 16

2.3.4 TCLP毒性浸出试验 17

第三章：研究结果及讨论 18

3.1 固化土基本物理化学特性研究 18

3.1.1固化土的含水率 18

3.1.2固化土的干密度 20

3.1.3固化土的酸碱度 21

3.1.4固化土的电导率 23

3.1.5本节小结 24

3.2 固化土化学稳定性研究 25

3.2.1概述 25

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