泥炭的微观结构及工程性质

从泥炭的微观结构分析入手,研究了泥炭的性质及特点,包括含水性质、强度性质、固结及次固结性质。通过对苏州泥炭、连云港淤泥、南通淤泥质土3种不同性质的软土进行固结试验,分析了泥炭地基与一般软土地基沉降速率的差别。提出了“次主沉降比”的概念和计算式,采用次主沉降比来确定次固结沉降与主固结沉降的比例。次固结系数与土的次主沉降比有一定关系,对于次主沉降比小于1的土,次固结系数变化很小,可以忽略不计;随着次主沉降比的增大,次固结系数的变化也增大。为了使沉降计算更可靠,建议泥炭地基的沉降计算采用平均次固结系数。

Micro-structure and Engineering Properties of Peat

Through analysis for the micro-structure of the peat,properties and characteristics of peat were studied,which include water content,strength,consolidation and secondary consolidation properties.By consolidation experiments of peat of Suzhou,mud of Lianyungang and muddy soil of Nantong,differences of settlement velocities between peat foundation and muddy soil foundation were analyzed.Based on it,the concept and calculation formula of secondary primary settlement ratio were put forward,which can determine the ratio of secondary consolidation settlement and primary consolidation settlement.There is certain relation between the secondary consolidation coefficient and the secondary primary settlement ratio,that is,when the secondary primary settlement ratio is less than 1,variation of secondary consolidation coefficient is very small,which even can be neglected;with the increase of the secondary primary settlement ratio,variation of secondary consolidation coefficient increases at the same time.Authors adopted an average secondary consolidation coefficient in settlement calculation of peat foundation in order to make results more reliable.