Research On Modification Of Anti-Seepage Material Of Earth-Rock Dam Core By Adding Gravel

Earth-rock dams are widely used in the construction of water conservancy projects due to their many advantages,such as simple structure,ease of construction and good adaptability to complex geological conditions.As the height of dams grows and the water storage height increases,higher demands are placed on the engineering properties of the core wall impermeable materials.In this paper,based on the current research status of the core wall impermeable soil materials and soil modification,a key project is proposed to use a wind-calculus-forming core wall soil materials to carry out the modification of gravel,bentonite,and study the proportion of gravel,moisture content and other influencing factors on the soil deformation,permeability,strength and the comprehensive characteristics of these three aspects of the law.The main research results are as follows:（1）Under the heavy compaction test,the dry density of the gravel-doped soil showed a law of change with the increase of the gravel-doping proportion,and the dry density of the soil reached its maximum value when the gravel-doping proportion P increased to 90%（P₅=77.0%）;under the light compaction test,the dry density of the gravel-doped soil increased approximately linearly with the increase of the gravel-doping proportion;the dry density of the gravel-doped soil gradually increased with the increase of the compaction work,and then The optimum moisture content of the soil mixture increases slightly with increasing gravel,while the maximum dry density of the soil does not change significantly.（2）The consolidation tests showed that the compression modulus of the soil increased with the increase of the proportion of gravel blending;the compressive modulus of the soil under high stress conditions decreased slightly when gravel blending was followed by bentonite,and at 95%compaction,the compressive modulus of the 35%gravel blended soil blended with 6%and 8%bentonite decreased by 9.6%and 9.8%respectively.（3）The soil materials with different gravel dosing ratios showed a strain-hardening type of stress-strain relationship;with the increase of gravel dosing ratio,the strength of the soil materials increased significantly;the overall strength of the soil mixture decreased after gravel dosing and then bentonite was added.（3）The Duncan-Zhang model parameters were derived from the stress-strain relationship curves of the soil samples.（4）Through the modification study of the proposed wind-deposited soil material for the core wall of this earth and rock dam,it was concluded that the compaction characteristics,compression characteristics and mechanical properties of the soil material mixed with 35%gravel and 6%bentonite were significantly improved,and the impermeability performance was good,meeting the requirements of engineering specifications.