3 results about "Earth pressure balance" patented technology

The invention discloses a device judging whether or not an earth pressure balance shield earth chamber is full. The device comprises a pressure detector disposed on the upper portion of a front shield earth chamber of the earth pressure balance shield; the signal output end of a pressure sensor is connected with an upper computer; the upper computer judges whether or not the chamber is full; if not, a warning signal is sent to an alarm unit. The device has the advantages that whether or not the earth chamber is full can be judged anytime during earth pressure balance shield tunneling, full-chamber shield tunneling can be ensured and the application of full-chamber tunneling decreases the danger of collapse ahead.

A process of boring a tunnel using an earth-pressure balance shield boring tunnelling machine having a cutting head, an excavation chamber for soil removed by boring and conveying means for removal of said soil from the excavation chamber; wherein there is injected into a stratum being bored at the cutting head a foamed aqueous solution, characterised in that (a) the aqueous solution contains two essential components which are (i) a sulphate- or sulphonate-containing anionic surfactant, and (ii) beta -naphthalene sulphonate-formaldehyde condensate; and in that (b) there is applied to the soil removed by boring in at least one of the excavation chamber and the conveyor a second aqueous solution containing essentially a high molecular weight polyethylene oxide and optionally a sulphate- or sulphonate-containing anionic surfactant. The process allows easy removal of soil from the cutting head to the excavation chamber and from the excavation chamber out of the machine. It is particularly effective for sticky soils with high proportions of clay and a high water content.