【摘要】：為了使工業(yè)副產(chǎn)品木質(zhì)素在粉土路基中得到更好的應(yīng)用,采用室內(nèi)無側(cè)限抗壓強(qiáng)度試驗、三軸壓縮試驗和掃描電鏡試驗,研究木質(zhì)素改良粉土的剪切強(qiáng)度特性和微觀結(jié)構(gòu),分析木質(zhì)素?fù)搅�、養(yǎng)護(hù)齡期對改良土強(qiáng)度和破壞特征的影響,探討不同圍壓和排水剪切條件下改良土的應(yīng)力-應(yīng)變關(guān)系,闡述木質(zhì)素產(chǎn)生的膠結(jié)作用對土體剪切特性的影響,并研究臨界狀態(tài)下改良土的剪切強(qiáng)度特征。試驗結(jié)果表明:改良土體無側(cè)限抗壓強(qiáng)度隨木質(zhì)素?fù)搅吭黾佣黾?過高摻量會造成強(qiáng)度降低,木質(zhì)素的添加可增強(qiáng)粉土的韌性特征,對于江蘇粉土的木質(zhì)素最優(yōu)摻入質(zhì)量分?jǐn)?shù)為12%;終值偏應(yīng)力隨圍壓和摻量增加而增大,其增量隨圍壓增加呈降低趨勢;低圍壓條件下,剪切過程會產(chǎn)生吸力,改良土孔隙水壓力在各圍壓下均小于素土;低圍壓排水剪切條件下,改良土體積應(yīng)變存在先"剪縮"后"剪脹"的變化特征,高圍壓條件下則完全表現(xiàn)為"剪縮";木質(zhì)素產(chǎn)生的膠結(jié)物質(zhì)填充孔隙并增強(qiáng)土顆粒間聯(lián)結(jié),土體形成更為致密、穩(wěn)定的微觀結(jié)構(gòu);改良土臨界狀態(tài)線相對于素土僅發(fā)生平移,黏聚力可用來表征木質(zhì)素對土體臨界狀態(tài)強(qiáng)度特性的影響;臨界狀態(tài)下木質(zhì)素改良土剪切特性的研究可為其本構(gòu)模型建立提供一定的基礎(chǔ)。
[Abstract]:In order to make the industrial byproduct lignin be better used in silt subgrade, the shear strength characteristics and microstructure of lignin modified silt were studied by laboratory unconfined compressive strength test, triaxial compression test and scanning electron microscope test, the effects of lignin content and curing age on the strength and failure characteristics of improved soil were analyzed, and the stress-strain relationship of improved soil under different confining pressure and drainage shear conditions was discussed. The effect of lignin bonding on the shear properties of soil is described, and the shear strength characteristics of improved soil in critical state are studied. The results show that the unconfined compressive strength of the improved soil increases with the increase of lignin content, and the strength decreases with the increase of lignin content. The addition of lignin can enhance the toughness characteristics of silt. For Jiangsu silt, the optimal lignin content is 12%, and the final bias stress increases with the increase of confining pressure and content, and the increment decreases with the increase of confining pressure. Under the condition of low confining pressure, the suction will be produced in the shear process, and the pore water pressure of the improved soil is less than that of the plain soil under each confining pressure. Under the condition of low confining pressure drainage shear, the volume strain of the improved soil has the characteristics of "shear shrinkage" first and then "shear expansion", while under the condition of high confining pressure, the cementitious material produced by lignin fills the pores and strengthens the connection between soil particles, and the soil forms a more compact and stable microstructure. The critical state line of improved soil is only shifted relative to plain soil, and the cohesion can be used to characterize the effect of lignin on the critical state strength characteristics of soil, and the study of shear characteristics of lignin modified soil in critical state can provide a certain basis for the establishment of its constitutive model.
【作者單位】： 中國地質(zhì)大學(xué)(武漢)工程學(xué)院;東南大學(xué)交通學(xué)院;
【基金】：國家自然科學(xué)基金項目(41330641,41202203) 高等學(xué)校全國優(yōu)秀博士學(xué)位論文作者專項資金項目(201353) 教育部新世紀(jì)優(yōu)秀人才支持計劃項目(NCET-13-0118) 中央高�；究蒲袠I(yè)務(wù)費專項資金項目(2242013R30014) 江蘇省杰出青年基金項目(BK20140027) 江蘇省交通科學(xué)研究計劃項目(2013Y04)
【分類號】：U416.1

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