The Study On The Surface Grouting Experiments In The Karst And Shallow-buried Area Of M.t Tongluo Tunnel

Grouting is an engineering technology, which has good practicability and is widely used. In the highway engineering construction in China at present, it brings difficulties to the design and construction of groutings due to the lack of applications, tests and studies in grouting and not having a full methodology system and regulations of technology. Therefore, it is necessary to take comprehensive and in-depth studies in grouting, and to form a set of technique that is fit for the grouting of road tunnels in the highway engineering construction in China.Focusing on the karst and the shallow-buried area of M.t Tongluo tunnel of Dian-Lin highway in this paper, the surface grouting technology of M.t Tongluo tunnel is studied systemically based on the experiments of grouting materials, designs of the grouting, experiments of the field grouting, the measures and evaluations on the quality of grouting. The main results are as follows:1. The grout that be fit for the test region and the optimum proportion was screened out by the orthogonal experiment of different grouts. The result of the test indicated that cement grout and cement-waterglass grout were fit for the grouting engineering in the karst and shallow-buried area. The recommended water-cement ratio of the cement grout is 1:1, and the volume ratio of cement and waterglass in cement-waterglass grout is 1:1.2. The studies indicated that the regressive-grouting is suitable for the projects of grouting in the area which has structure-cracked and low-intension stratum. Therefore, the regressive-grouting is recommended for the project of grouting in the karst and shallow-buried area in Liaojia channel.3. Through the observation of grout filling, the analysis of grout quantity, the water permeability of the rock, the results of sonic wave test and the contrast of compressive strength of the rock core, it is indicated that the water permeability of grouted stratum was under 5 Lu, the average increase rate of sonic wave speed was 11.5%, and the average increase rate of compressive strength of the rock core was 11%.4. Using the method of AHP-Fuzzy comprehensive Evaluation and the evaluating criterions of the integrality, continuity and consistency of grouting cartier, an evaluating system of grouting quality which is suitable for the karst area was built with 8 indexes such as warter permeability, soundwave speed, the integrality of the rock, the decrease rate of the cement volume per meter and the permeability of simple water-pressure test, the compressive strength of the rock and the type of the curve in normative water-pressure test through the studies. A "nice" result was figured out by the general evaluation of grouting quality on the basic of AHP-Fuzzy comprehensive Evaluation with the measuring data.5. The parameters of grouting were optimized according to the process and the result of gounting, and the optimized parameters which were fit for surface grouting in the karst and shallow-buried area in Liaojia channel were given as follows: the maximum pressure of grouting is 1.5MPa, the penetration radius is ranged from 1～1.5m, and the volume of single-hole grouting may be ranged from 9～13m~3.