Anti-seepage Technique By High-Pressure Jet Grouting In Strata With Big Grain Size

In our country, lots of hydro projects, which were built or are being built or will be built, are located in strata with big grain size. The strata with big grain size mean the nonuniform strata in which the percentage of grain more than 2cm constitutes the majority, including gravel strata, erratic block form, rubble layer and their mixing layer. This kind of strata is distributed widely in the Quaternary overburden layer of mountain riverbeds and mountain sloping field. In addition, the backfill layer with stone blocks and rock dregs and building derelict also belongs to the strata with big grain size. In the strata with big grain size, it is of strong permeability. Under the action of water head, the serious water leakage leads to the foundation out of stability and buildings damaged. It needs anti-seepage and strengthening treatment when building on the strata with big grain size. The anti-seepage concrete wall and static curtain grouting and other ways are often used in the traditional treatment. It is difficult for the above-mentioned ways to meet the demand of project quality and time limits with high cost because of technics and technical causes. If it is not be treated properly in foundation, it will leads to serious losses. Thus, the study on the anti-seepage technique by high-pressure jet grouting in strata with big grain size is of great social and economic significance.There are four parts in the paper, including the introduction of the high-pressure jet grouting technique, the technique of building impervious wall by high-pressure jet grouting in strata with big grain size, the application examples in projects and conclusion. In the second part (the high-pressure jet grouting technique in strata with big grain size), it elaborates the wall forming mechanism by high-pressure jet grouting in strata with big grain size, high-pressure grouting design, construction technics and equipments, quality monitoring of wall body and blocking technique for leakage passage. Two project examples are introduced in the third part.In the result of anti-seepage technique by high-pressure jet grouting in strata with big grain size, it sets forth the high-pressure wall forming condition and mechanism in strata with big grain size in a theoretical way, puts forward the design principle and construction equipment and technics. The anti-seepage and strengthening technique has been raised to a new level with great economic and social benefits.