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Experimental research on horizontal flexible reinforced grouting with physical model
Abstract
The mass data in whole process of physical model test were real-time recorded; and the implementing mechanisms, reinforcement efficiency, construction technology of new horizontal flexible reinforced grouting technology were studied with physical model test in field. This paper focuses on the test design, manufacture scheme of model, testing method and research methods of experimental research. The test results show that the new horizontal flexible reinforced grouting technology contains enormous advantages including easy processing, effectiveness, and development and utilization value. It is indicated by the results of the experiment that the test results combining with the theoretical calculation have the guiding meaning for modifying the designing parameters. Meanwhile, the test results and construction parameters of the new technology can be used in real design and similar engineering for the test conditions of model test are basically in consistence with the conditions of actual operation.
For the difficult problem of the quality testing of grouting, laboratory test, dynamic penetration test and geological radar test method were used to measure the reinforcement effect after grouting throughout grouting model test and it was found that mechanical parameters and bearing capacity were increased and the continuity and integrity were improved, which was compared with the real results reflected by the full section excavation. The results show that the bearing characteristics and the slurry distribution patterns are basically the same in both. The soil physical and mechanical properties are significantly improved, and soil stabilization enhances, continuity and integrity are improved. Integrated laboratory test, dynamic sounding test and geological radar test method can better reflect the grouting reinforcement effect in loose soil, and offer certain reference and guidance for the grouting effect detection in loose filled soil.
The construction technology, implement mechanism, reinforcement efficiency of implementing method of backfill of abutment back with horizontal flexible-reinforced grouting technology were studied by in-situ experimental research combining with laboratory study. The in-situ test results show that the backfill of abutment back reinforced by the new horizontal flexible reinforced grouting technology has enormous advantages including easy processed, effectiveness, development and utilization value. On the processing of the in-situ test many valuable construction parameters and experimental data were obtained; and a lot of material resource could be used for changing the design and construction parameters so as to perfect the construction technology of the new technology. At the same time, a new engineering solution for the prevention and treatment of bridgehead jump-driving was offered.
Dams are mainly located at the deep alluvium, where large amount of sand and gravel is adverse to prevention of seepage and maintenance of stability of the dams. Therefore it is necessary to reinforce the dams by grouting, and the primary task is to do research on the laws of diffusion and distribution of the slurry in the alluvial layer. The present study is based on the traditional theory of grouting and the laws of diffusion and distribution of the slurry, the slurry splitting mechanism, the characteristics of soil reinforcement are obtained. In addition, it is found by on-site grouting model tests that the slurry is generally filling and splitting along the interface between the earth and rock, and mainly splitting in the horizontal direction in grouting reinforcement process. To improve the reinforcement effect, the repeated injection should be adopted in grouting process. The study results will facilitate future dam grouting reinforcement projects in alluvial layer.
Bolt and grouting reinforcement is an ideal measure for improving performance of bearing capacity of soft surrounding rock around tunnel in soft rock. Based on the test and research for fluidity, performance of separating water and compressive strength of fly ash and cement grouting material in laboratory, grouting material with a proper mixture rate is found (fly ash column fraction is less thorn 20%, water to cement ratio is from 0.65 to 0.70). An engineering practical example is given that fly ash and cement grouting has been used in very soft rock roadway at the Xinji NO.3 mine in Huainan.