岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2013年
z2期
74-80,87
,共8页
胡幼常%申俊敏%赵建斌%顾光斗%蔡华南
鬍幼常%申俊敏%趙建斌%顧光鬥%蔡華南
호유상%신준민%조건빈%고광두%채화남
掺砂黄土%土工格栅加筋%回弹模量%无侧限压缩%室内试验
摻砂黃土%土工格柵加觔%迴彈模量%無側限壓縮%室內試驗
참사황토%토공격책가근%회탄모량%무측한압축%실내시험
loess mixed with sand%geogrid-reinforcement%resilient modulus%unconfined compression%laboratory test
为了寻找实用而有效的方法来降低用黄土填筑的桥头路堤沉降并提高其强度以避免桥头跳车,提出了在黄土中掺砂、用土工格栅加筋或两种方法同时采用的建议。为了研究这些建议的可行性,采用室内回弹模量试验和无侧限抗压试验分别研究了土工格栅加筋黄土和加筋掺砂黄土的变形和强度特性。对黄土和掺砂黄土分别完成了压实度为88%、92%和96%,加筋层数为0~5层组合工况下多组试样的回弹模量和无侧限抗压试验,对试验结果进行了详细的对比分析,得到以下结论:(1)掺砂和土工格栅加筋都可以明显提高黄土的回弹模量,两种方法同时使用效果更佳;(2)不管有无土工格栅加筋,掺砂都能使黄土强度大幅度提高,尤其在小应变下其提高的幅度更大;(3)在压实度不变而加筋层数增多时,或加筋层数不变而压实度下降时,土工格栅加筋掺砂黄土的应力-应变曲线由应变软化型逐渐向应变硬化型转变;(4)加筋掺砂黄土存在筋-土强度合理匹配问题,压实度高时应布置较密的加筋层,以使二者变形协调,从而实现加筋掺砂黄土强度的最大化。
為瞭尋找實用而有效的方法來降低用黃土填築的橋頭路隄沉降併提高其彊度以避免橋頭跳車,提齣瞭在黃土中摻砂、用土工格柵加觔或兩種方法同時採用的建議。為瞭研究這些建議的可行性,採用室內迴彈模量試驗和無側限抗壓試驗分彆研究瞭土工格柵加觔黃土和加觔摻砂黃土的變形和彊度特性。對黃土和摻砂黃土分彆完成瞭壓實度為88%、92%和96%,加觔層數為0~5層組閤工況下多組試樣的迴彈模量和無側限抗壓試驗,對試驗結果進行瞭詳細的對比分析,得到以下結論:(1)摻砂和土工格柵加觔都可以明顯提高黃土的迴彈模量,兩種方法同時使用效果更佳;(2)不管有無土工格柵加觔,摻砂都能使黃土彊度大幅度提高,尤其在小應變下其提高的幅度更大;(3)在壓實度不變而加觔層數增多時,或加觔層數不變而壓實度下降時,土工格柵加觔摻砂黃土的應力-應變麯線由應變軟化型逐漸嚮應變硬化型轉變;(4)加觔摻砂黃土存在觔-土彊度閤理匹配問題,壓實度高時應佈置較密的加觔層,以使二者變形協調,從而實現加觔摻砂黃土彊度的最大化。
위료심조실용이유효적방법래강저용황토전축적교두로제침강병제고기강도이피면교두도차,제출료재황토중참사、용토공격책가근혹량충방법동시채용적건의。위료연구저사건의적가행성,채용실내회탄모량시험화무측한항압시험분별연구료토공격책가근황토화가근참사황토적변형화강도특성。대황토화참사황토분별완성료압실도위88%、92%화96%,가근층수위0~5층조합공황하다조시양적회탄모량화무측한항압시험,대시험결과진행료상세적대비분석,득도이하결론:(1)참사화토공격책가근도가이명현제고황토적회탄모량,량충방법동시사용효과경가;(2)불관유무토공격책가근,참사도능사황토강도대폭도제고,우기재소응변하기제고적폭도경대;(3)재압실도불변이가근층수증다시,혹가근층수불변이압실도하강시,토공격책가근참사황토적응력-응변곡선유응변연화형축점향응변경화형전변;(4)가근참사황토존재근-토강도합리필배문제,압실도고시응포치교밀적가근층,이사이자변형협조,종이실현가근참사황토강도적최대화。
In order to find out an effective and practical approach to reduce the settlement and increase the strength of an approach embankment filled with loess so as to avoid the bump at bridgehead, the methods were suggested by mixing a proportion of sand into the loess or reinforcing the loess with geogrid, or by using these two skills together. For examining essentially the feasibility of these ideas, the deformation and strength properties of geogrid-reinforced loess, loess mixed with sand (LMS) and geogrid-reinforced LMS were investigated in laboratory. A series of resilient modulus tests and unconfined compression tests were conducted respectively using samples made up of LMS or pure loess either with or without geogrid-inclusions. Each sample varied either in the number of reinforcement layers from 0 to 5, or in the degrees of compaction of 88%, 92%or 96%. Based on a detail analysis of the test results, the following conclusions are drawn:(1) The resilient modulus of the loess increases significantly either by mixed with sand or by reinforced with geogrid. More improvement is demonstrated while the both methods are applied together in a loess sample. (2) The compressive strength of LMS is much greater than that of loess when the LMS and the loess both are either with or without geogrid inclusions, especially under small compressive strain. (3) The compressive stress-strain pattern of a geogrid-reinforced LMS changes gradually from strain-softening to strain-hardening either while the geogrid layers increase at a certain degree of compaction or when the degree of compaction decreases at a given geogrid layers. (4) There is an appropriate strength match between the geogrid and the LMS, according to which a geogrid-reinforced LMS with higher density is suggested to be reinforced with smaller reinforcement spacing so as to obtain a maximum strength derived from a compatible deforming between the geogrid and the soil.