Abstract: A surface of a fresh concrete body is dried by first covering the surface to be dried with a layer of bibulous granules having a great internal surface area for a time sufficient to draw generally all of the water out of the body via the surface and then preventing water from entering the layer from its side turned away from the body. The granules are finely divided hygroscopic particles, with an internal surface area of at least 200 m.sup.2 /g, preferably at least 800 m.sup.2 /g. The hydrophilic particles take up the moisture from the concrete and hold it in the layer of particles lying on the surface. This reduces the partial vapor pressure on the surface of the concrete body which effectively draws further liquid out of the concrete. The particles are a mixture of a cross-linked polymer that only swells in water and silica. The particles are carried in a coherent mat and are applied as a layer to the surface by laying the mat thereon.

Abstract: A track support element for a maglev track has an upper member consisting of a steel fiber concrete plate provided with the mounting elements for attachment of the maglev rails, stator and the like. This plate is connected by steel struts to a lower member which can be a steel tube filled with steel fiber concrete.

Abstract: A reinforcement comprises a group of generally parallel, longitudinally extending, and transversely spaced multifilament cables extending in a concrete mass and each having a pair of longitudinally opposite ends. A respective longitudinally extending resin sheath surrounds each cable between its ends and a plurality of spacers spaced longitudinally along the cables and their sheaths hold same transversely apart with the concrete mass extending between the sheaths. An anticorrosion and antifriction agent inside each sheath surrounds each cable inside the respective sheath between the respective cable ends and a respective anchor braces each cable end against the concrete mass.

Abstract: In my process for digging a tunnel with the help of a tunnel excavator which has a working chamber under atmospheric pressure, the local front wall is supported with the help of a pressurized medium which is connected by a controlling gap of a shield cover with another gap between a shield cover tail and/or the earth or ground and a tunnel-lining member. The gap is closed-off from the working chamber by a gap-sealing ring between a shield cover tail and a tunnel-lining member. Concrete is forced into the gap by a feeder pipe in the gap-sealing ring. A self-sealing permeable joint between the gap-sealing ring and the shield cover tail and/or the tunnel-lining member of the excavator is made with concrete which has a fine-grained additive material and a large-grained additive material so that the large-grained additive material forms a grain filter whose pores are closable by the fine-grained additive material.

Abstract: The movable tight-sealing ring is positioned between an excavator cover end and a form or casing structure. For a satisfactory movability of the excavator cover end interstice, the tight-sealing sealing ring is supported resiliently by adjustable supporting units freely movable relative to the excavator cover end and the casing or form structure. On one side the tight-sealing sealing ring is provided with a plurality of impressed material feed openings and on the other side with an elastic outer sealing member contactable on the inside of the excavator cover end as well as an elastic inner sealing member pressable against the outside of the form or casing structure.

Abstract: A form for a concrete tunnel lining usable behind a tunnel excavator with a traveling shield is made of an inner tunnel-lining sheathing and a form front. The inner tunnel-lining sheathing is divided into a plurality of sheathing segments or rings movable independently of each other with intervening segment-bridging yieldable joints. The form front located between the traveling shield and the inner tunnel-lining sheathing is movable forwardly by the conrete which presses in the annular space formed by the traveling shield and/or the surrounding earth and by the inner tunnel-lining sheathing as well as the form front. An operationally beneficial design results when the inner tunnel-lining sheathing is set up for forward motion of the sheathing segments in the tunnel longitudinal direction singly or in groups one after the other relative to the remaining sheathing segments held or remaining at rest.

Abstract: A process for lining a tunnel with concrete behind a tunnel excavator having a for front advanced along with an excavator head in which the concrete is forced between the surrounding subterranean geological structure and an inner tunnel-lining form through a form front which rides sealingly on the outer surface of the inner tunnel-lining form and on the inner surface of the shield. Simultaneously, the form front, which is longitudinally movable relative to the shield, moves forward relative to the inner tunnel-lining form. The form front is movable forward simultaneously balancing the friction forces occurring between the form front and the shield and the inner tunnel-lining form. Satisfactory results are obtained when the friction forces between concrete sections of a predetermined length are measured by moving the form front relative to the stationary shield and the inner tunnel-lining form during an interruption in concrete feed.

Abstract: The earth pressure shield for a tunnel and/or gallery excavator has a front working compartment formed by a separating wall having a digging tool and an annular reinforcing space substantially triangular in cross section positioned directly in front of the separating wall. So that an extensive restructuring of the machine is not necessary when moving from soft earth to hard ground, the annular reinforcing space is provided with a lower fluid feeder, a controlled upper pressurized air feeder, a plurality of fluid conductor pipes which are guided from below to an upper fluid outlet opening into the working compartment, and a fluid level controller. The invention is based on the consideration that a reliable and satisfactory support of the local front wall is only possible when the local front wall in the vicinity of the roof can be supplied with a fluid.

Abstract: The earth pressure shield contains a front working compartment having a digging tool and formed by a separating wall. An annular space is formed in the front working compartment with a top region connected with a regulated pressurized air feed and with a bottom region open to the digging tool so that dug or mined earth material is removable with the help of a conveyor unit. At least one fluid pipe is guided from a fluid chamber with a level controller and a fluid feeder to a fluid outlet open to the digging or mining tool in the working compartment. An especially reliable operation is attained when a bulkhead space is provided by partitioning behind the working compartment and/or the circular space formed with an immersed wall. This bulkhead space is connected in its upper region with the top region of the annular space by an opening in the separating wall and includes the fluid chamber in its lower region.

Abstract: The apparatus for applying a sprayed concrete layer to a surface comprises a concrete feed pipe for a pumpable and sprayable concrete mixture made with water, a sprayer and a compressed air feed device for compressed air under a pressure of several bar from a compressed air source. The concrete feed pipe opens into the sprayer which has a compressed air connector device. The concrete mixture is sprayable with the compressed air. The compressed air feed device comprises a register including several compressed air chambers which connect to and open into the compressed air connector device. The individual compressed air chambers are connected with the help of control valves in alternating sequence to a power silo for loading a powdery concrete additive, particularly silica powder, or for blowing through a compressed air partial flow.

Abstract: A spray concrete composition which is sprayed with driving-air pressure has its setting time accelerated by incorporation in the driving air of amorphous silica dust having an inner surface (specific surface area) of at least 25 m.sup.2 /g.

Abstract: An apparatus for making a tunnel lining from concrete in a single operation with a tunnel excavator comprises a tunnel lining form consisting of a plurality of tunnel lining form segments and a form front adjacent the tunnel excavator and a tunnel lining circular space between the form and the ground. The concrete is selected so that it remains workable for more than two hours at a temperature of about 20.degree. C. but sets to a nonworkable state after 10 to 30 minutes upon heating to a temperature in the range of substantially 40.degree. C. to substantially 70.degree. C. The concrete is heated in a pipe section proximal to the compartment into which it is introduced by direct introduction of electrical energy into the pipe section.

Abstract: The apparatus for making a substantially vertical slot in the ground in a step in making a sealing or supporting wall comprises a frame member, a supporting shield, at least two cutting wheels and a drive unit. The supporting shield is attached to the frame member and supports the cutting wheels and the drive unit. The cutting wheels are mounted on a common shaft and at least a portion of the drive unit is enclosed by at least one of the cutting wheels. A housing projecting pipe like on both of its opposing sides is attached to the supporting shield. Each of the cutting wheels have a hub which is mounted on a common shaft mounted in the housing. A hollow drive wheel is provided for the cutting wheels and is mounted advantageously on a stepped in seat on one of the hubs. It fits in the housing with play. The hollow drive wheel meshes with a plurality of drive gears each connected to a drive motor.

Abstract: The apparatus for making a substantially vertical slot in the ground, especially in a single operation in making a sealing or supporting wall, comprises a machine frame with a rectangular cross section guided in the slot in the ground with a plurality of guide surfaces and at least one driven cutting wheel positioned at the lower end of the machine frame. The machine frame and the cutting wheels have a width which correspond to the width of the slot in the ground within tolerances defined by the guide free play and the cutting free play. The machine frame is guided in the vertical slot with a plurality of guiding surfaces and comprises an upper guide frame and a lower guide frame. The cutting wheels are mounted on the lower guide frame. The controlling piston cylinder unit for control of the lower guiding frame is mounted between the upper and lower guiding frames.

Abstract: The digging tool of the tunnel excavator is mounted on a shield support and operates in a forward digging chamber. The digging chamber is sealed from a tunnel formed by the excavator by a separating wall of the excavator across a transverse cross section of the excavator. The digging chamber is filled with a fluid which supports the forward digging chamber wall. The problems resulting from the incompressibility of the supporting fluid can be handled simply when the digging chamber, with at least a portion of its separating wall, is supported so as to be movable longitudinally back and forth by an adjustable spring device. Advantageously, the spring device comprises a plurality of hydraulic cylinder devices whose cylinders are connected to a hydraulic accumulator under gas pressure.

Abstract: An apparatus for making a tunnel lining from concrete in a single operation with a tunnel excavator comprises a tunnel lining form consisting of a plurality of tunnel lining form segments and a form front adjacent the tunnel excavator and a tunnel lining circular space between the form and the ground. In order to heat the concrete as it is pumped into the tunnel lining circular space to accelerate hardening, transmitting antennae for electromagnetic radiation are mounted in the tunnel lining form segments and/or the feed pipes for the concrete. Similarly a process for making a tunnel lining from concrete comprises pumping concrete into the tunnel lining circular space and accelerating the hardening of the concrete by heating it with electromagnetic radiation. The tunnel form is rapidly repositioned after the concrete being hardened reaches a sufficient strength.

Abstract: A process for providing a corrosion resistant synthetic plastic resin coating on a surface of a concrete structure comprises cleaning the surface of the concrete structure, forming a fiber containing sprayed concrete layer having a plurality of fiber components therein, for example glass fibers or plastic fibers, on the surface of the concrete, and subsequently applying a synthetic plastic resin thereto, whereby the fiber components projecting from the fiber containing sprayed concrete layer act to anchor the synthetic plastic resin to form the corrosion resistant coating. The corrosion resistant synthetic plastic resin coating preferably contains a polyester resin, and a polymer-cement-concrete base layer may be used to help bond the fiber containing sprayed concrete layer to the cleaned concrete surface.

Abstract: A tunneling machine with a leading ring, a follower ring, an overlapping joint connection between the leading ring and the follower ring, a pressure ring, advancing piston/cylinder assemblies, and a roll correction device. The advancing piston/cylinder assemblies are distributed about the shield circumference, and they are connected on the one hand by the way of linkages to the pressure ring, and on the other hand they are supported at the leading or shield ring. The roll correction device has a roll correction ring which is arranged in the leading ring, and the roll correction ring can rotate with respect to the leading shield. The roll correction ring is also supported by a thrust-absorbing bearing. The advancing piston/cylinder assemblies are movably joined at the roll correction ring, and are indirectly supported at the leading ring.

Abstract: A tunneling apparatus has a lateral shield having a front end normally engaged longitudinally against a tunnel end face, a digging tool at the front end of the shield and engageable with the tunnel face, and a drive for displacing the tool and digging the tunnel face. A transverse pressure wall across the shield forms a pressurizable chamber inside the front end of the shield around the tool at the tunnel face. A conveyor tube longitudinally traverses and has a front end open ahead of the wall in the chamber and adapted to receive material freed from the tunnel face by the digging tool. An auger can be rotated in the tube to displace freed material back in it from its front end to its rear end. A chute opens upward into the rear end of the conveyor tube to receive material therefrom and a pump tube extends longitudinally back from the chute. A piston pump between the chute and the pump tube can displace material from the chute back in the tube.

Abstract: A tunneling machine of the type having a leading shield, a trailing shield, an annular form connected to the trailing shield by respective cylinder units for the emplacement of the concrete behind the machine and cylinder units for relatively advancing the leading and trailing shields, is also equipped with a telescoping shield assembly with its own set of cylinder units so that the concrete emplacement can be decoupled from the advance of the cutting head on the leading shield.