Study On Prediction Method For Post-Construction Settlement And Stability Of High Ifll Of Harbor Area Based On Second Deformation Modulus

The land area project with high fill in the southwest of our country is existed in theconstruction of inland ports. While the stability of land area project is affectedimmediately by unequal settlement of post-construction of high fills, and the safety andnormal operation of structures are also threaten with that. So how to predict the unequalsettlement of post-construction on continent high fill effectively and evaluate whosestability correctly is one of key technical problem that continent high fill of ports urgentwants to solve. At present, as the detection index of controlling post-construction,second deformation modulus is widely used in Europe country, such as Germany,however, which is only applied on railway embankment in China, and there has norelevant rules in design standards of highway engineering, continent high fill of portsengineering and slop engineering, and so on, to this end, we propose a settlement ofpost-construction prediction method of continent high fill of ports and evaluate whosestability, based on the second deformation modulus. For predicting the settlement ofpost-construction effective and evaluating the stability correctly, we use experimentalresearch, theoretical analysis and numerical simulation to study the second deformationmodulus deeply, and then, based on that, the settlement of post-construction predictionmethod in high fill of harbor is proposed and the stability is also evaluated. In this paper,the main achievements are summarized as follows:(1) According to the field test principle of second deformation modulus, makespecimens with compaction canister, which are used to test in the laboratory under thecondition of lateral confinement, and then through the analysis of numerical simulationon test equipment, the feasibility of laboratory test method is verified. The researchresult shows that the results of laboratory test and numerical simulation have a goodconsistency, and the border restriction of laboratory test equipment has no effects onexperimental results.(2) Based on the laboratory testing method of second deformation modulus, a largeamount of specimen was tested with that method, and the influence rule of seconddeformation modulus on the factors which are water content, porosity, compactiondegree and saturation are studied. The research result shows that all of the factors havedifferent effects on the second deformation modulus. When the soil is in the optimummoisture, its second deformation modulus will reach peak. When the non-uniformity coefficient is biggest, the second deformation modulus is also biggest. We also foundthat the second deformation modulus is decreased with the decreasing of porosity of soil,and increased with the increasing of compaction degree, Meanwhile, the seconddeformation modulus of weathered sandstone soil is less than weathered mudstone soil.(3) According to the field test principle of second deformation modulus, large scalefill foundation model is built which is tested second deformation modulus and studiedwith numerical simulation, the compaction degree of specimen is consistent with the fillfoundation model and made by volumetric method which is tested in laboratory. Theresearch result shows that boundary effect of model test would be negligible, thelaboratory test result agrees well with the model experiment. Based on the large numberof test result above, a laboratory test method of second deformation modulus isproposed which has characteristics with convenient, fast, cheap.(4) Based on the study of laboratory test and elastic-plastic theory, the seconddeformation modulus is derived, and then the theory formula is obtained. Through thecomparative analysis of theory calculation and laboratory test, it shows that thelaboratory result is agree with theory result well, Even though there has some certainerrors, because the Poisson's ratio is adopted as0.21directly according to regulations,which is between0.2and0.3in spot filed test. So the theory calculation formula isfeasible.(5) Based on research of theory and experiment, it found that the height anddeformation modulus play an important role in settlement of high fill foundation. Soempirical relation between second deformation modulus and post-constructionsettlement is built on the basis of elastic-plastic theory, and an evaluation method ofpost-construction of high fill foundation on port area is proposed. Meanwhile,foundation coefficient is a common index on high fill foundation at present, so therelevant relationship between second deformation modulus and foundation coefficient isfurther studied with numerical simulation method, and then the result shows that both ofthem has good correlation.(6) For high fill project which has been built, whose second deformation modulus canbe obtained with field test, and then be calculated post-construction settlement, finally,compare the value of calculation to actual observation, thus, the stability of high fillproject can be judged preliminary. For high fill project which will be proposed, whosesmallest second deformation modulus can be obtained according to the largest post-construction settlement which is allowed in the design requirements, meanwhile, backfill can be chose through laboratory test, which can make the second deformationmodulus to meet the design requirements. Therefore, after construction finished, thesecond deformation modulus can be obtained through field test, and then the post-construction settlement also can be obtained, which is compared to the design value,thus, it can judge that whether or not meet the design requirement.(7) The practical application shows that, include high fill projects of Naxigou wharf,Yuanshanzi and Changan test track, based on the second deformation modulus, thevaluation method of post-construction settlement of high fill foundation on port areasbrings about good results, and it also has certain significance for design andconstruction.