The Research Of The Construction And Seepage Character On Cohesive Soil In The Plain Area Of Western Shandong

The seepage problem that the plain reservoir of western Shandong exists is caused by permeability of the cohesive soil of dam foundation. The understanding that the permeability of the cohesive soil is one-sided in the past, while geology is reconnoitred, find its general macrostructure, influence the permeability directly. This thesis announces its seepage mechanism gradually on the basis of studying cohesive soil's construction, offer the reliable practice basis for the fact that the follow-up seepage is designed.The research contents include the constitutive property, cermeability and seepage stability of the cohesive soil mainly. Divided six parts to describe totally.Cohesive soil is constitutive property: Cohesive soil have macroscopical hole construction generally, namely clay's crevice construction, macropore construction of loam and sandy loam of clay, Introduce its basic distribute regulation with the characteristics of the concomitant ginger nut.The origin cause of formation of the cohesive soil's macroscopic pore construction analyses, have narrated the forming process of the loam's macropore construction, and has carried on the contrast to the structure characteristic of the cohesive soil in terms of seepage pressure with capillary water.Permeability of the cohesive soil: Cohesive soil's constitutive property determines its permeability. Cohesive soil's seepage character to have typical anisotropism, and coefficient of permeability is different in different hydraulic gradient and position. The general cohesive soil is regarded the isotropic body approximately, its permeability is little, belong to the weak general little filter layer. But cohesive soil have constitutive property is different, its coefficient of permeability is very great, it is a strong filter layer. Begins from the basic regulation of the incohesive soil at first, extends to the definite method to the cohesive soil's coefficient of permeability.The seepage controlled of the cohesive soil: The seepage of dam foundation can be divided into three stages, namely vertical seepage stage, free seepage stage and crossrange seepage stage; Calculate the formula and course, the measure is used with seepage control of dam foundation in the plain reservoir at present, including the level defend and the vertical combinative defend; the complex geomembrane is used with the compact cohesive soil's seepage control on mass of dam.Seepage stability of the cohesive soil: Seepage deformation pattern of cohesive soil is solifluction mainly ,the cohesive soil's cosent gradient ratio is confirmed by locale test of seepage deformation. The seepage deformation problem from the incohesive soil to the cohesive soil, includes pattern and cosent gradient ratio confirmed, and the compact cohesive soil's seepage deformation character.A large amount of research work has been done in investigating process with the reservoir of plain area of western Shandong and conveyance circuit, the structure to the cohesive soil realizes, has carried on the contrast from the stratum in each area, find that has universality, has done the photo record. In the demonstration of the relative aquifuge, a series of pumping locale test have done to the cohesive soil, summarize influence factor and conversion law that the cohesive soil's coefficient of permeability. In out of seepage deformation, locale test of seepage deformation highly reliable, so in large-scale reservoir investigating locale test is done to various kinds of cohesive soil, have confirmed the cosent gradient ratio in the studying area.Through the above research approach, draw the following conclusion.1.Cohesive soil have macroscopical hole construction generally, namely clay's crevice construction, macropore construction of loam and sandy loam of clay.2.Different drilling crafts will exert a different influence on the cohesive soil's constitutive property, undisturbed soil can only reflects the cohesive soil's constitutive property truly.3.Because of "crack clay" clay content high, It comes into being by dehumidifying to shrink and aircrack. And the formation on large macropore construction of loam is more complicated, analyses in aspect of mineral composition, construction form and seepage regulation etc.4.Cohesive soil's constitutive property determines its permeability.5.The cohesive soil can transform from the aquifuge into the aquafer under certain condition.6.Besides dispersed cohesive soil, Seepage deformation pattern of cohesive soil is solifluction mainly.7.The cohesive soil's cosent gradient ratio is confirmed by locale test of seepage deformation.8.The crack clay than fall crack can heal by oneself in small hydraulic slope, and heal part can be consolidation in course of fill slowly,the cosent gradient ratio will have certain improvement.