围绕引江济淮工程膨胀土地段河渠边坡水泥改性土换填层易碱化板结、植物难以生长和局部弱膨胀土渠坡 的简化处理等工程实际问题，以生态优先、技术创新为原则，采用现场试验、室内单元体测试和数值分析等手段， 开展系统的研究工作。研发一种改善水泥改性土种植效果的生态基材，提出一种新型膨胀土双层护坡结构，并研 究提出根据实际土层膨胀特性和含水状态进行弱膨胀土边坡的处理原则。现场中试和运用效果表明：研发的生 态基材能适应水泥改性土的种植需要，使边坡实现良好的绿化效果，双层护坡结构较好地实现了膨胀土边坡防止 降雨入渗和水分蒸发的双重防护要求；同时，还可利用砂土层的压重效果，抑制土层的膨胀变形。研究成果为引 江济淮的工程设计和后期运行管理提供了技术支撑，同时，也为膨胀土地段渠坡生态处治探寻了新的方向。

Total?length?of?the?Yangtze-to-Huaihe?Water?Transfer?Project?is?723?km,?more?than?100?km?of?the?river section?is?distributed?with?weak?and?medium?expansive?soil,?and?the?maximum?excavation?depth?of?the?canal?is?46 m.?The?stability?of?the?expansive?soil?section?is?one?of?the?key?technical?problems?of?the?project.?In?the?preliminary design?stage,?the?treatment?measures?of?over?digging,?replacing?and?filling?cement-modified?soil?were?proposed?for the?expanded?land?section,?but?some?ecological?and?environmental?problems?were?generated,?such?as?the?cement modified?soil?is?easy?to?be?alkali,?and?makes?it?difficult?for?plants?to?grow.?Moreover,?slope?overcutting?would produce?a?large?amount?of?waste?soil?which?is?adverse?to?the?ecological?environment.?Whether?simplified?treatment measures?can?be?applied?to?some?weak?expansion?channels?with?slope?heights?less?than?10?m?is?a?question?that?needs to?be?addressed.?Under?the?principle?of?ecological?priority?and?technological?innovation,?the?researchers?carried?out systematic ?research ?work ?using ?field ?experiments, ?indoor ?unit ?tests, ?and ?numerical ?analysis. ?The ?ecological restoration ?scheme ?using ?surface ?cultivated ?soil ?and ?grass ?was ?put ?forward ?through ?field ?sampling ?tests ?and numerical?analysis?for?the?low?river?embankment?in?the?weak?expansive?soil?around?Chaohu?Lake.?An?ecological substrate?was?developed?to?solve?the?problems?such?as?soil?alkali?plate?and?plant?growth?difficulty?in?the?medium expansive?cement-modified?soil?replacement?layer.?The?field?pilot?test?proved?that?the?ecological?substrate?is?a?new kind?of?ecological?slope?planting?material.?An?ecologically?friendly?expansive?soil?slope?protection?structure?is proposed?using?unsaturated?soil?theory?based?on?the?characteristics?of?a?large?difference?in?permeability?coefficient between?sand?and?clay.?This?structure?can?better?solve?the?dual?protection?requirements?of?expansive?soil?slopes?to prevent?rainfall?infiltration?and?water?evaporation.?At?the?same?time,?it?can?also?use?the?compression?effect?of?the sand?layer?to?restrain?the?expansion?and?deformation?of?soil?layer. ??????The?field?pilot?test?and?application?results?show?that?the?ecological?substrate?developed?can?adapt?to?the?planting needs ?of ?cement-modified ?soil ?so ?that ?the ?slope ?can ?achieve ?a ?good ?greening ?effect. ?The ?double-layer ?slope protection?structure?can?better?solve?the?dual?protection?requirements?of?the?expansive?soil?slope?to?prevent?rainfall infiltration?and?water?evaporation.?The?expansion?and?deformation?of?the?soil?layer?can?also?be?controlled?by?the compression?effect?of?the?sand?layer. ??????The?research?results?provide?technical?support?for?the?engineering?design?and?late?operation?management?of?the project,?effectively?solving?the?technical?problems?related?to?the?expansion?land?section?of?the?project,?and?provide?a basis ?for ?the ?design ?and ?optimization ?of ?related ?river ?slope. ?Together, ?breakthroughs ?have ?been ?made ?in ?the engineering?application?of?unsaturated?soil?theory?and?the?ecological?treatment?of?expansive?soil?slopes.