Relation Between The Content Of The Fine Particles Of Wide Grading Soil And The Uplift Pressure Of Check Dam Base

By penetration test the upper limit particle size of fine particle that affects the permeability of the wide grading soil and the relation between the content of the fine particles and the permeability coefficient are confirmed, and by uplift pressure model test the relation between the permeability coefficient of the gully soil and the uplift pressure of the dam base is confirmed. Based on two testing results the relation between the content of the fine particles of the wide grading soil and the uplift pressure of the check dam base is obtained. The result can provide a basis of how to calculate and control the uplift pressure in design of check dam. All experimental conclusions are as follows:(1) The upper limit particle size of fine particle that affects the permeability of the debris flow wide grading soil is confirmed. The upper limit particle size of fine particle that observably affects the permeability of the wide grading soil is 0.1mm;(2) The relation between the content of the fine particles and the permeability coefficient is studied. The relation of the content of the fine particles p and the permeability coefficient k in the wide grading soil is negative exponential function, and relation formula is k=ne-p/m that n associates with the permeability of coarse particles and m associates with the permeability of fine particles.(3) The distribution characteristics of the uplift pressure of dam base is analyzed.The uplift pressure of the dam base P is inversely linked to the seepage route L, and the relation formula is P=a-bL that a associates with the water head and the debris in front of dam and b associates with the slope and the permeability of gully.(4) The relation between the permeability coefficient and the uplift pressure of dam base is discussed. The uplift pressure of the dam base P is proportional to the the constant logarithm of permeability coefficient of the debris in the front of the dam lgk, and the relation formula is P= a+b lgk that a associates with the water head and the slope of gully and b associates with the slope of gully. The uplift pressure of the dam base P is proportional to the permeability coefficient of the gully soil k, and the relation formula is P= a+bk that a associates with the water head and the slope of gully and b associates with the slope of gully.(5) The relation between the content of the fine particles in the debris flow wide grading soil and the uplift pressure of dam base is initially built.The relation of the content of the fine particles in the wide grading soil p and the uplift pressure of the dam base P is negative exponential function, and the relation formula is = + -/ that y associates with the water head in front of dam, A associates with the permeability of coarse particles and the slope of gully and c associates with the permeability of fine particles. Lowering the water head in front of dam or reducing the permeability coefficient of the gully soil will decreasing the uplift pressure of the dam base. Adding fine particles into gully soil that decreases the permeability coefficient of the gully soil is a possible way to decrease the uplift pressure of the dam base obviously.