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Nagasaki University H. Sakanoshita Y. Tanabashi Y. Jiang S.Sugimoto K.Ogawa

THE REINFORCEMENT AND CONSTRUCTION METHOD FOR EMBANKMENT BY USING LOW QUALITY SURPLUS SOIL AND MUNICIPAL WASTE INCINERATOR ASHES. Nagasaki University H. Sakanoshita Y. Tanabashi Y. Jiang S.Sugimoto K.Ogawa. Back ground of research. Municipal solid waste incinerator ashes (MSWI ashes).

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Nagasaki University H. Sakanoshita Y. Tanabashi Y. Jiang S.Sugimoto K.Ogawa

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  1. THEREINFORCEMENTANDCONSTRUCTIONMETHODFOREMBANKMENTBYUSINGLOWQUALITYSURPLUSSOILANDMUNICIPALWASTEINCINERATORASHESTHEREINFORCEMENTANDCONSTRUCTIONMETHODFOREMBANKMENTBYUSINGLOWQUALITYSURPLUSSOILANDMUNICIPALWASTEINCINERATORASHES Nagasaki University H. Sakanoshita Y. Tanabashi Y. Jiang S.Sugimoto K.Ogawa

  2. Back ground of research Municipal solid waste incinerator ashes (MSWI ashes) 研究の背景 • Increase rapidly with the economic growing • Risk of environmental pollution • Lack of the disposal space Low quality sludge (Ariake clay) Low quality sludge (Ariake clay) • Difficult for usage • Remarkable rise of disposal cost • Limit of the disposal space The resource recycling of them is an urgent problem

  3. Purpose of research disposed to harmless Mixture pavement and filling material Integral construction Mechanical characterization Chemical characterization centrifugal model experiment numerical simulation Evaluation of usability MSWI ashes 研究の目的 Low quality sludge Ecoash New type construction material Evaluation

  4. Processing flow of recycling system リサイクルシステム Dust collector Storage equipment Melting equipment Activated carbon adsorption Chimney Fixed quantity supply equipment Fly ash Exhaust gas Exhaust gas Additives A Dryness equipment The magnetic separator The first response equipment Crusher Crusher Additives B Decomposition of dioxin The second response equipment The first processing ashes tank Production Product tank Stabilization of heavy metals Decomposition of dioxin Stabilization of heavy metals

  5. The characteristics of Ecoash 56.3 53.17 エコアッシュの物性値

  6. The characteristics of Low Quality Surplus Soil 20500 179 139 97.2 有明粘土の物性値

  7. Results of the unconfined compression test RL＝5％ RL＝1％ Target strength 300kPa Mixing condition 一軸圧縮試験結果 • Water content of Ariake clay W ≒ 139％ • Saga Ecoash：Ariake clay＝50：50 • Ratio of the slaked lime RL＝ 0，1，2，5％ Slaked lime addition is an important factor

  8. 重金属溶出試験 Heavy metals leaching test Possible to suppress the elution of heavy metals

  9. Centrifugal model Experimentpreparation 80G ×80 Experiment on age 14 days Experimental device 遠心模型実験概要 Model scale 50cm wide， 14cm deep 40m wide，11.2m deep Real ground scale Saga Ecoash ：Ariake Clay＝50：50， Ratio of the slaked lime RL＝1％ Improvement layer and Filling are made Experiment on age 14 days

  10. Outline of model ground Cut out clay layer and construct improvement and Fill after self-weight consolidation Loading plate descends with a rate of 0.05mm/s while acting centrifugal acceleration of 80G Clay layer with water content about 100% is prepared Loading Fill Loadingplate Gradient of slope 1：0.6 Improvement 20 120 D B (1) 52.5 Clay layer 250 (3) (2) 57.5 模型地盤概要図 (Unit：mm) Earth pressure gauge

  11. Experiment cases B D B B D D Fill Improvement Clay layer

  12. 荷重強度-土圧関係① Failure Fill is not stable Unimproved Load-earth pressure(1) (1) Earth pressure gauge(2) (2) (3) Case N Earth pressure gauge(1) Earth pressure gauge(3)

  13. 荷重強度-土圧関係② (2) (2) (2) Case LS，Case LD Case SS Touch area is large It cannot spread load Breadth is small The friction effect is large Load-earth pressure(2) Earth pressure gauge(2) Case SS Case LS Case LD

  14. 荷重強度-沈下量関係 Settlement depression effect Large Case N Case SS Case LS Small Case LD Load-settlement curve

  15. Outline of analytical model (1) A clay layer model with surface reinforced is assumed as 80 times of centrifugal model. A clay layer model with surface reinforced is assumed as 80 times of centrifugal model. 数値解析概要① Analysis procedure Analysis code FLAC3D Construct clay Yield criterion Cut out clay layer Mohr-Coulomb Construct improvement and fill Loading method 60kPa loadings (By 6 stages, each of 10kPa) Loading

  16. Outline of analytical model (2) Analytical Cases 数値解析概要② The same as experiment case Analytical physical property

  17. Failure region (after loading 60ｋPa) Concentration of stress Case LS Improvement loses bearing capacity Tension failure in the early stage Failureregion (before loading) 破壊領域 None Shear Tension Case SS Case LS

  18. Numerical simulation case 解析ケース

  19. 7.7/1.0 5.8/1.5 9.6/1.0 5.8/1.0 The lower end breadth of filling is smaller than the breadth of the improvement, therefore the settlement depression effect is small. The settlement depression effect by the extension of improvement depth D is large Load-settlement curve 荷重強度-沈下量関係

  20. Conclusions Integral construction is effective Mixture (Ecoash，Low quality sludge，Slaked lime) 結論 Mechanical characterization & Chemical characterization • Sufficient strength • Chemical stable and harmless to public health Centrifugal model experiment & Numerical analysis • Fill was steady by integral construction with pavement Could be used as a high performance geo-material

  21. SS（Analysis） SS（Analysis） LS（Analysis） LS（Analysis） Effect of tension failure is large Settlement is larger than Case SS LS（Experiment） SS（Experiment） SS（Experiment） Analysis Theslippage was not generated in the boundary in clay layer and improvement Displacement is small Load strength – settlement curve 荷重強度-沈下量関係 Case SS Case LS

  22. pH measurement test pH測定試験 Ariake clay 7.1 Hasuike clay 5.8 10.6 Ecoash 12.5 Slaked lime 12.2 Ecoash/clay mixture 0 2 4 6 8 10 12 14 pH PbCl2＋Ca(OH)2→Pb(OH)2＋CaCl2 2Na3AsO4＋3Ca(OH)2→Ca3(AsO4)2＋6NaO Ecoash/clay mixture can be purification effect of the soil pollution and oxidation depression effect.

  23. The surface layer improvement Ecoash Slaked lime Ariake clay tubercle 表層改良工法 Side floating Soft ground unimproved Bearing stratum improvement Soft ground Ariake clay Surface layer improvement Bearing stratum

  24. 熱の流れ HCｌｶﾞｽの流れ CaO+HCl→CaCl2+H2O 粉砕灰＋　添加剤A(石灰系） DXNs分解　HCl　ｶﾞｽ発生 原灰 （ダイオキシン類分解メカニズム） CaCl2　：　融点　７７２℃ 焼成炉温度： 　７７２℃以上：CaCl2液化 　　　　　　　　　再合成しやすい 　７７２℃以下：CaCl2固体→安定

  25. 《重金属類固定化メカニズム》 (鉛固定化メカニズム） ①硫化反応：　PbCl2　＋　Na2S　→　PbS　＋　2NaCl ②水酸化反応： 　　加水混練による処理灰中石灰分のイオン化 Pb2+ + 2Cl- + Ca2+ + 2(OH)-　→　Pb(OH)2+ CaCl2 各種鉛化合物の溶解度積 数値が大きいほど溶解し難い

  26. (六価クロム固定化メカニズム） 　　　　　クロムの酸化・還元反応による価数の変化 Cr2O72－＋14H＋＋6ｅ-　　　　　　２Cr3＋　＋　７H2O 焼却過程で安定な三価クロムが酸化反応により六価クロムとなり、 硫化薬剤の還元作用により再び三価クロムへ変化することで安定化する。 還元反応 酸化反応 《重金属類固定化メカニズム》

  27. 重金属安定化ﾒｶﾆｽﾞﾑ：ｐH • 強アルカリ性及びﾌﾘｰﾃﾞﾙ氏塩生成による重金属安定化 強アルカリ性となり、水酸化物あるいは 低溶解度度化合物を生成する PbCl2+Ca(OH)2 →Pb(OH)+CaCl2 2Na2AsO4 + 3Ca(OH)2 →Ca3(AsO4)2+6NaOH

  28. Pb，Asの安定化 Pb (鉛) 混合することで生じる化学式 PbCl2 + Ca(OH)2 → Pb(OH)2 + CaCl2 水酸化物 As (ヒ素) 2Na3AsO4 + 3Ca(OH)2 → Ca3(AsO4)2 + 6NaOH 低溶解度化合物

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