典型岩溶石山山坡土壤剖面水分分层性特征及其影响因素

【目的】揭示岩溶石山山坡土壤剖面水分的分层性及其与土壤理化性质间的相互关系,为我国南方岩溶地区石漠化治理、水土流失和岩溶水文过程等研究提供科学依据。【方法】选取典型岩溶石山山坡土壤剖面进行分层取样,结合统计分析方法,研究岩溶石山地区土壤水含量的垂向分布特征及其影响因素,分析土壤剖面水含量的分层特征。【结果】岩溶石山山坡土壤剖面水含量具有明显差异,变化范围为34.66%~47.10%,平均值为38.15%,土壤质量水含量的最大值出现在35 cm深处。相关性分析结果表明,土壤质量水含量与有机质含量呈显著正相关(P<0.05,下同),与pH呈显著负相关,与中值粒径相关性不显著(P>0.05);有机质通过改善土壤团聚体结构影响土壤质量水含量变化。土壤质量水含量及理化性质的变化具有分层性,地表至35 cm为表土层,35~85 cm为过渡层,85~115 cm为稳定层。【结论】岩溶石山地区土壤剖面水分具有明显的分层性,是土壤性质、结构特征、根系活动、水分运动、化学淋滤作用及基岩界面综合作用的结果,尤其应注意20~40 cm处植被根系活动及基岩界面对土壤剖面水分变化的影响。

Study of elastic-plastic damage model of cement consolidated soil with high organic content

On the basis of elastic-plastic damage model of cement consolidated soil,the authors took organic contents into reasonable damage variable evolution equation in order to seek relation between the organic contents and parameters in the equation,and established the elastic-plastic damage model of cement consolidated soil considering organic contents.The results show that the parameters change correspondingly with difference of the organic contents.The higher the organic contents are,the less the valves of the parameters such as elastic modulus(E),material parameters(K,n) and damage evolution parameter(ε) become,but the larger strain damage threshold value(εd) of the sample is.Meanwhile,the calculation results obtained from established model are compared with the test data in the condition of common indoors test,which is testified with reliability.