黏粒含量对固化淤泥力学性质的影响

INFLUENCE OF CLAY CONTENT ON MECHANICAL PROPERTIES OF SOLIDIFIED SILT

采用人工配制不同黏粒含量的淤泥研究黏粒含量对固化淤泥力学性质的影响。研究发现,淤泥中黏粒含量对固化淤泥的力学性质存在显著影响,当水泥量为5.0%时,固化淤泥强度随黏粒含量的增加呈增加趋势;当水泥量高于7.5%时,对于不同水泥量都存在一个对应的适宜黏粒含量CCop,在该黏粒含量时固化淤泥的无侧限抗压强度最大,破坏应变最小。适宜黏粒含量CCop随着水泥量增加而有所增加,但龄期对其没有影响。三轴试验结果发现,当黏粒含量为CCop时固化淤泥黏聚力c达到最大,内摩擦角?则随黏粒含量的增加呈现减小趋势。对于不同黏粒含量下固化淤泥的应力–应变关系的研究发现,当水泥量不超过5.0%时,固化淤泥都表现出理想弹塑性的特性;当水泥量大于5.0%时固化淤泥都存在破坏峰值,表现出脆性破坏模式,而且随着黏粒含量的增加破坏应变先减小后增加;当黏粒含量为CCop时,固化淤泥对应的破坏应变接近最小。因此,当黏粒含量为CCop时,固化淤泥将出现最大强度和最小变形。该研究结果对淤泥固化实际应用中的材料配制具有重要意义。

The silts dredged from ocean,lake and river always have different clay contents which lead to different strength of solidified silts.Silts with different clay contents are prepared;and the influence of clay content on mechanical properties of solidified silt is tested.It is discovered that different clay contents have remarkable influence on the mechanical properties of solidified silt.When the cement content is 5.0%,the strength of the solidified soil increases with the clay content increasing.When the cement content is above 7.5%,an optimum clay content（CCop） is showed,which is corresponding to the different cement contents.When the clay content is equal to the CCop,the maximum unconfined compressive strength and the minimum failure strain of solidified silt can be obtained.The numerical value of CCop increases with cement content increasingly lifting,but freatment time has no effect on it.The triaxial experiments show that the solidified silt with CCop has the maximum cohesion index,however,the angle of internal friction decreases with the increase of clay content.At the same time,the stress-strain relationship of solidified soil with different clay contents is also researched.The results show that,if the cement content is below 5.0%,the stress-strain relationship of solidified soil behaves ideal elastoplastic characteristics;if the cement content is above 5.0%,the stress-strain relationship behaves brittle failure characteristics,meanwhile,there is a peak value.Moreover,the failure strain decreases earlier but increases later with the clay content rising,while the clay content is up to the optimum one,the failure strain approaches to the minimum.So solidified soil will behave the maximum unconfined compressive strength and the minimum strain.The results have great significances for the design of solidified agent in practical engineering.