Research On The Test And Evaluation Of The Bonding Quality Of The Cemented Materials Dam

Cemented materials dam is a new type of dam,which has the advantages of over-topping and non-collapsing,economic and safe,fast construction,and environmentally friendly.The cemented materials dam adopts a roller compaction construction method similar to that of a roller compacted concrete dam.The construction quality of roller compaction and the construction quality of the interface between layers are related to the safety and stability of the dam.Therefore,there must be a suitable method for the quality of the roller compaction(including the interlayer).Perform testing and evaluation.Existing methods for detecting the quality of rolling construction are digging method and densimeter method.The former is time-consuming and laborious,and the latter includes the limited use of nuclear densitometer,and the non-nuclear densitometer cannot detect the density of large-depth cemented sand and gravel;combined The detection method of surface construction quality is mainly through manual inspection and empirical qualitative description,which has the disadvantages of low efficiency and large error,and cannot meet the requirements of fast construction of cemented materials dams.This paper first carried out the indoor and outdoor verification test for the rapid detection of the density of cemented sand and gravel with a thickness of 50-60 cm by a large-depth nuclear-free density detector;secondly,the factors and influences of the shear strength of the cemented sand and gravel layer were tested indoors.The law has been tested and studied;third,the in-situ direct shear test was carried out on the cement dam site to verify whether the bonding quality of the cemented sand and gravel dam body and the contact surface of different materials meets the requirements of anti-sliding stability;fourth,the development based on digital image processing The quality inspection and evaluation technology of the roller compacted bonding surface of the cemented materials dam.The main results and conclusions are as follows:(1)The applicability of the special non-nuclear density meter for cemented sand and gravel with a detection depth of 50-60 cm is verified.The indoor test results show that the correlation coefficient between the measured density value and the real density value is above 0.9.The demonstration application on the project site shows that as the number of rolling passes increases,the measured density value at each point also increases good.(2)The indoor shear strength test of cemented sand and gravel layer was conducted.The main indicators were shear cohesion and pure abrasion cohesion,and the resistance under different ages,intervals between layers,and different layer treatments were discussed.The change law of compressive strength,shear resistance cohesion and pure abrasion cohesion.The results show that cleaning and roughening significantly improves the strength ratio of the specimen,and at the same time can effectively increase the roughness of the cold seam,increase the friction force,and then increase the friction coefficient,which has a greater impact on the quality of layer bonding;several treatment methods The order of the effect is:air gun cleaning up the exposed stones and adding mortar>cleaning and fluffing and adding mortar>directly adding mortar>cleaning and fluffing>no treatment.(3)The cemented sand-gravel filling layer test with different sand-gravel aggregate content.The test results show that:the layer failure form It is mainly mixed failure type,showing plastic to brittle failure;with the increase of aggregate content,the concentration of aggregate at the section gradually increases,and the shear strength gradually decreases,which is more likely to occur along the plane of shear damage;shear resistance The peak strength is about 10～30%higher than the residual strength,shear strength and single-point friction strength.(4)Developed the cemented materials dam layer image acquisition vehicle,based on the digital image processing technology,proposed the quality evaluation index of the inter-layer bonding.The field test results show that the broken aggregate in this area accounts for 0.343%of the total area,and the area of the uneven area after scouring accounts for 68.0%.The index can indirectly reflect the construction quality of the layer.