摘要
通过青岛市唐岛湾沿岸7个实验工区的考察测试、实验分析、数据处理等,对现代泥质沉积物水下收缩裂隙的整体形成过程、定量分级、各参数间拟合关系、开裂规律以及充填物沉积模式等进行了详细研究,并且建立了相应的地质演化模型。裂隙整体形成过程分4个阶段,依次为:泥水混合物初始混浊阶段;沉积物压实稳定阶段;裂隙形成阶段以及裂隙充填阶段。裂隙形态定量分级可分别用横缝长、纵缝长、裂隙面积和基块面积等参数表示,共分4级。其中裂隙各参数之间的拟合关系以及开裂规律地质建模分析等,对于定量描述裂隙形态、结构、变化规律,预测区域性裂隙规模、判别区域沉积环境等具有重要意义。沙泥质地层裂隙开裂过程中的异常高压作用(形成机理与大地构造中的异常高压相似)以及裂隙分叉角度的统计分析(最多为90°,其次为120°)均属首次提出。其中异常高压作用对于初始裂隙的形成、沉积物粒间水的有效排出以及主要渗流通道的发育起到了重要作用。单一泥质地层裂隙内充填物沉积模式与沙泥互层的多旋回地层略有差异,主要表现为沙层的润滑作用以及对早期裂隙内充填物类型的影响。裂隙纵剖面中生物发育层的出现,对于裂隙内充填物的物理、化学性质将产生重要影响。
On the basis of expeditionary research and experimental analysis of seven work areas in the coastland of Tangdao Bay, this paper attempts to research the subaqueous mud-shrinkage cracks （SMSC） in present muddy sediments on some significant aspects, such as continuous course of forming cracks, quantitative classification, fitting relation of its parameters, pattern of crack growth, sedimentary models of filling compounds, and the respectively geologic succession models. The course of forming cracks is divided into four phases, as follows： （1） the turbid phase of mud-water mixtures in the beginning; （2） the compacted phase of muddy sediments; （3） the forming phase of SMSC; （4） the filling phase of SMSC. The quantitative grade of SMSC in the size is described by some parameters including the length of longitudinal crack or lateral crack, the area of cracks or crack segments and so on （having 4 grade）. The cracking pattern of mud cracks and the matched relation of its parameters are important characters to describe the physical and chemical properties of mud or soil, to reflect the environment of forming cracks and forecast the distribution of area cracks. The ＂abnormal pressure action＂ in the process of crack growth on sand-mud layer （the forming mechanism of abnormal pressure is similar with the one in the geotectonic framework） and the statistical analysis for angles of bifurcation （the maxima is 90°, the second is 120°） are all first putted forward to investigate SMSC, where the abnormal pressure plays an important role in initial step of forming cracks, discharging water from sedimentary pores, and developing on the primary flow matrix. It is different between the homogeneous layer and the sand-mud interbedded layer in many aspects, such as the lubricating action of sand layers and the initial filling style in shrinkage cracks. In vertical section of cracks, there is a biological layer, where seed plants can germinate and grow on suitable conditions, which has a vital func
出处
《地质论评》
CAS
CSCD
北大核心
2007年第3期306-317,I0001,共13页
Geological Review
基金
国家自然科学基金资助项目(编号40072042)的成果
关键词
水下收缩裂隙
定量研究
开裂规律
分叉角度
充填模式
地质建模
subaqueous mud-shrinkage crack
quantitative analysis
cracking pattern
angle of bifurcation
filling model
geologic model
