CAJ | 학술논문

抗拉强度是黏性土重要的力学指标之一.自行研制了简易土工拉伸仪,并通过试验确定了合适的制样方法.在此基础上,对具有胀缩性的武鸣红黏土和百色膨胀土分别进行试验,探讨了其抗拉强度与干密度、含水率、干湿循环次数等影响因素的关系,研究结果表明:两种土的抗拉强度-含水率曲线在饱和度接近66%时出现峰值,该峰值对应含水率接近最优含水率,峰值两侧呈指数关系变化,抗拉强度随含水率的变化规律受土中水的形态影响.抗拉强度随干密度的增加而线性递增,增加幅度显著.抗拉强度随干、湿循环次数增加而衰减,1~2次循环时,强度衰减幅度最大,但3次循环后,趋向于一稳定值,稳定值为初始值的20%左右,土体干、湿循环后抗拉强度降低是微结构劣化的结果.
항랍강도시점성토중요적역학지표지일.자행연제료간역토공랍신의,병통과시험학정료합괄적제양방법.재차기출상,대구유창축성적무명홍점토화백색팽창토분별진행시험,탐토료기항랍강도여간밀도、함수솔、간습순배차수등영향인소적관계,연구결과표명:량충토적항랍강도-함수솔곡선재포화도접근66%시출현봉치,해봉치대응함수솔접근최우함수솔,봉치량측정지수관계변화,항랍강도수함수솔적변화규률수토중수적형태영향.항랍강도수간밀도적증가이선성체증,증가폭도현저.항랍강도수간、습순배차수증가이쇠감,1~2차순배시,강도쇠감폭도최대,단3차순배후,추향우일은정치,은정치위초시치적20%좌우,토체간、습순배후항랍강도강저시미결구열화적결과.
Tensile strength is an important mechanical index of clay. A set of tensile strength apparatus is developed to test the tensile strength of clay and the specimen-preparing methods on tensile strength are studied. Tensile strength tests for two types of swell-shrink soils are respectively designed to discuss the influences of water content, dry density and drying-wetting cycles. Analysis of the data shows that there is an exponential relationship between tensile strength and water content;and the tensile strength reaches the peak value at optimum water content, saturation degree of 66%. And the change rule of tensile strength with water content is impacted by the forms of water in soils. It is also found that tensile strength linearly increases with dry density and the increase rate is significant. As experienced three dry-wetting cycles, the tensile strength sharply decreases to 20%of the initial value and its impact is especially obvious during the first and second cycles. Through theoretic and contrast analysis, it is found that the decrease of tensile strength of swell-shrink soils with drying-wetting cycles is due to the deterioration of microstructures.