Hiroshi MIYASAKA

A study on analysis and promotion of efficiency of the grouting of the crack-related bedrock using the construction example

Satoru OHTSUKA

It is the present conditions that is dependent on an execution example in the past or a law learned by experience without theoretical proof doing it in the decision of the execution parameter enough so that it is generally executed the work in the bedrock that viewing is impossible as for the used grouting as dam basics processing method of construction. As a result, the case that the construction that it is thought with a case and the excessiveness which additional construction produces is constructed occurs without an injection effect to expect being provided. Furthermore, the cost cut becomes indispensable because there are the social conditions to surround the construction business in the severe situation called the public-works spending reduction.

On the basis of such situation, this study studied Welded tuff of the volcano rock which a prominent crack was distributed over in bedrock and analyzed the behavior of the grout in the crack from momentary pressure, the injection data which recorded flow quantity and room injection experiment result in the past in the real injection spot and examined the enforcement point to let you fill it effectively without a grout delaying in the volcanic rock where a prominent crack was distributed over.

I got the following knowledge from the analysis based on the construction example with the volcano rock which these consecutive cracks were distributed over.

­¡ I can grasp the permeability that adapted itself to the injection situation by adopting Lugeon value after the destruction that linked the greatest pressure to the origin. ­¢ I can grasp crack width to affect the viscosity of the grout by adopting Lugeon value after destruction quantitatively. ­£ When Lugeon value are more than 5, I can inject a grout in a crack after destruction effectively by assuming injection start combination less than W/C=2. ­¤ As for the injection pressure, the grout arrives at the range to aim for in 1.0MPa.

By the grouting that consecutive cracks limited to a distributed volcano rock from these results of research, I adopt Lugeon value after destruction for the decision of injection specifications and because Lugeon value 5 injects the grout of the high density by low pressure in high water permeance region more than it after destruction, I restrain the outflow of the grout to an unreasonable range and shorten injection time, and an improvement effect is provided effectively.

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