Patent ID: 12209498

DETAILED DESCRIPTION

FIGS.1and2illustrate 3D views of a general thrust shell100comprising a main hallow can170and thrust ring160that is connected to thrust cylinders150of the TBM310. So the movement (pushing/pulling) of the Thrust shell100will be controlled by TBM310's thrust cylinders150.

The thrust shell's ring may be comprising stiffeners180on the Thrust ring160if needed structurally. The thickness of the hallow can170of the Thrust shell100may be thicker at the thrust ring160area structurally. However, the extra thickness will be toward inside of the thrust ring160.

The hallow can170will be able to move back and forth within the gap between TBM310's trailing shield312and segmental rings172/174. Therefore, ID of the thrust can170should be more than OD of the segmental ring172/174, and OD of the thrust can170should be less than ID of the TBM310's trailing shield312.

An expandable Ring110will be positioned at front of the previously installed segmental ring172and lining. (SeeFIG.8a) The main function of the Expandable ring110is to transfer pushing load from the TBM310's thrust cylinders150and thrust shell100to the previously installed segmental ring172. The expandable ring110is comprising a plurality (2, 3, 4, 5 or such) of sectors190(most likely with cross section of hollow square or hollow rectangular) with required stiffeners that are connected by circumferential cylinders/jacks120. Therefore, the expandable ring110is able to be expanded or collapsed between two different diameters by extending or retracting of the circumferential cylinders120.

The circumferential cylinders120can be either made by hydraulic piston or screw jack system or similar systems. At expanded mode, the OD of the expandable ring110is almost equal to OD of the thrust shell and ID of the expandable ring110is almost equal to ID of the segmental ring172/174. At collapsed mode, the OD of the expandable ring110is less than ID of the segmental ring172/174to be able to move within the segmental rings172/174.

While TBM310is pushing against the installed segmental ring172via thrust shell100and expanded expandable ring110and advancing forward by expanding TBM's thrust cylinders150, a new segmental ring174will be built within inner space of the thrust shell's hallow can170space by TBM310's segment erector316. (SeeFIG.8bandFIG.8c).

The segments for the new segmental ring174will be contacted by jacks130and140in axial direction of the tunnel at segment's circumferential leading and trailing sides. The axial jacks130at the segment's circumferential leading side of the segment are mounted on the thrust ring160and the axial jacks140at the segment's circumferential trailing side of the segment are mounted on the expandable ring110.

The axial jacks130and140may be made by hydraulic or screw-jack system or similar. Alternatively, the axial jacks130for the circumferential leading side of the segment may be mounted within the stationary shield314of the TBM310, similar to TBM310's thrust cylinders150. In this case length of those axial jacks130will need to be longer.

Numbers of the axial mounted jacks130and140may be equal to nos. of the dowels at each face of the segmental ring172/174. Depending on the design, numbers of the axial mounted jacks130and140will be equal but might be less (e.g. half) of the numbers of the dowels at each face of the segmental ring172/174. The thrust shell100's axial mounted jacks130and the expandable ring110's axial mounted jacks140should be aligned with dowels locations at leading and trailing side of the segments.

Before starting segment erection for a new segmental ring174within the thrust can170, all axial jacks140of the expandable ring110will be extended to their required position.

TBM310's segment erector316will be erecting the new segmental ring174almost like the typical/conventional segmental lining. It will bring each segment to its position where expandable ring110's axial jack(s)140will be contacted with the segment and segment erector316will be holding the segment till axial mounted jacks130on the thrust shell100will be extending and contacting with the segment and then the segment will be hold. The segment erector316will bring the next segments one by one for erection and to complete a full segmental ring174. Connection method at radial sides of the segments in a ring (bolt, Post-tensioning strand, etc.) should be completed at this stage.

For better contact between segments and mounted axial cylinders, short struts200will be mounted to the shoes faces of the axial jacks130and140that will be entered in the segment's dowel holes during the segment erection. Thus, the erected segmental ring174will be stable and kept at circle shape and hence oval-shaping of the new segmental ring174can be avoided. Furthermore only if necessary, the segment erector316of the TBM310can temporarily hold the new segmental ring174from its inner side at the crown portion to help preventing the oval-shaping of the new ring till its installation to the previously installed ring174.

As soon as the segmental ring174is completed within the thrust shell100(and also TBM310advancement cycle completed for one full segmental ring174), then all axial jacks140of the expandable ring110will be retracted and subsequently all circumferential cylinders120of the expandable ring110will be retraced as well to collapse the expandable ring110. (SeeFIG.8d) Then Segment erector316will be lifting the expandable ring110from its upper side of lowest sector210and therefore space between previously installed segmental ring172and newly erected segmental ring174will be clear. (SeeFIG.8e) The dowels between new segmental ring174and previously installed ring172may be installed at this stage.

Since ID of the expandable ring's all sectors190/210is equal to ID of the segments, the segment erector316can grab the upper side of the lowest segment210of the expandable ring110, lift and move it almost like a segment. Alternatively, segment erector316can grab, lift and move the expandable ring110from its bottom side of upper sector220as well.

The segment erector316of the current conventional/typical TBM310smay need some modifications for this operation to carry weight of the expandable ring110(which might be more than its capacity), also geometrically to adopt width of the lowest sector210(or upper sector220) of expandable ring110which may have less width than concrete segment in most of the cases.

Further, lowest sector210(or upper sector220) of the expandable ring110will be designed such a way that, their inner side can accommodate the segment erector316suitably. For instance, circumferential cylinders120connected to the mentioned sectors210/220can be spaced enough to have more room for the segment erector316. Also connection points of circumferential cylinders120to those sectors210/220can be located within inside space of the sectors210/220(instead of their inner side) to provide more room for the segment erector316.

The newly erected segmental ring will be pushed by axial mounted jacks130to its final position to contact and connect (by dowels) with the previously installed segmental lining, and thrust shell100will be pulled out by retracting TBM310's thrust cylinders150to its new position. (SeeFIGS.8fand8g).

Then segment erector316will bring the expandable ring110to its new position at leading side of the last ring and afterward circumferential cylinders120will be extended to expand the expandable ring110. Then thrust shell100will be pushed to contact with the expandable ring110and start pushing TBM310forward and concurrently another new segmental ring174erection will be commenced within the can170. (SeeFIGS.8gand8h).

The only downtime/stoppage of the excavation and segment erection can be assumed to be almost equal to time needed for one segment erection by segment erector316since segment erector316will be lifting the collapsed expandable ring110and will move that to its new position, almost similar to one segment installation required time. As example it would be estimated that for a tunnel lining with 6 segments per segmental ring, speed of the tunnelling may be increased around (6−1)/6×100=83.3% theoretically. I.e. speed of the tunnelling would be increased around 1.83 times theoretically.

Current conventional/typical TBM310's trailing shield312will need to be longer (around 1.5 times of the segmental ring172/174width longer) to accommodate the thrust shell100and expandable ring110. E.g. if segment width is 1.2 m, then length of TBM310would be around 1.80 m longer.

In most of the cases it won't be necessary to increase TBM310's diameter to accommodate the thrust shell100system as existing gap between TBM310's trailing shield312and segmental lining174would be enough for operation of the thrust shell100. However only if needed, diameter of the current conventional/typical TBM310might be necessary to slightly increase.

As self-weight of the thrust shell100as well as self-weight of the newly erected segmental ring174within the thrust shell100will push the thrust shell100down to trailing shield312, optionally in order to reduce relevant frictions between thrust shell100and new segmental ring174, and also friction between thrust shell100and TBM310's trailing shield312, plurality of strip rollers230/235may be connected at least at bottom part of the thrust shell100within the hollow can170. As shown atFIGS.3and3aexample, two groups of strip rollers may be utilized including inner strip rollers230and outer strip rollers235. Top side of the inner strip rollers230are in contact with surface of the new segmental ring174and bottom side of the outer strip roller235are sitting on the trailing shield312. Optionally such strip rollers230/235may be used at all around the can170to reduce friction at all perimeter. Generally single rollers may be used instead of strip rollers230/235as well.

After connection of new and previously installed segmental rings174and172(e.g. by dowels) and pulling the thrust can170out of the newly erected segment ring174perimeter, the mentioned segmental ring174will be suspended from the previous segmental ring172and can be settled lower due to its self-weight (See stage atFIG.8g). There may be couple of ways to avoid settlement of the new segmental ring174.

As first option, thrust can170may be extended permanently at gap260locations between sectors190of the expandable ring110(at least at lowest gap locations), such away that the segmental ring174can be still sit on the extension portions of the thrust can170even after pulling the thrust can170out from around of the latest segmental ring174. Therefore width of the extended portions of the thrust can170would be less than length of the gaps260between sectors190of the expandable ring110, and length of them would be couple of feet more than width of the expandable ring110to be able to reach to around of the latest segmental ring174with sufficient overlap with the segmental ring174.

The second option would be still pushing and holding the latest segmental ring174to the previously erected lining by couple of the axial jacks130which have been located at the gaps260between sectors of the expandable ring110. In this case those jacks that will be still contacted to the latest segmental ring174's leading circumferential side should have long enough stroke for pushing and holding the latest segmental ring174even after pulling the thrust can170out. Then those jacks can be retracted after positioning of the expandable ring110at front of the latest segmental ring and thrust can170started pushing the expandable ring110which will subsequently hold the latest ring174.

Alternatively one or plurality of inflatable tube rings may be added to the trailing shield312of TBM310that would be inflated to temporarily hold the last segmental ring174(See stage atFIG.8g) whenever needed. Obviously, combination of above-mentioned options may be utilized as well, if necessary.

After expanding of the expandable ring110, due to the existence of the gaps260between sectors190of the expandable ring110(seeFIGS.1and2), the segmental ring172won't be taking TBM310's thrust push pressure at the gap260areas (SeeFIG.8astage). This issue may cause tensile (spalling) stresses at the segmental ring172at mentioned gap260areas and may cause cracks on the segments (assuming made by concrete at this case) if occurred spalling stresses are more than concrete segment's tensile capacity.

As a solution for this issue (if necessary), additional telescopic curve beams240may be added to inside of the end portion of the sectors190of the expandable ring110which can move inside the sectors190within rails or guidance and will cover the gap260between the sectors190. Each telescopic curve beams240will comprise additional axial jack250at its middle part that can be extended and contacted with the segmental ring172circumferential leading side at gap260areas. Therefore, thrust pressure of the TBM310will be transferred via the mentioned additional jacks250to the segmental ring172at gap260portions as well. Before collapsing of the expandable ring110, those jacks250on the telescopic beams240will be retracted and will be able to entre to inside of the sectors190while the expandable ring110is collapsing. SeeFIGS.4aand4bshowing mentioned telescopic beam240and its mounted axial jack250at expanded mode of the expandable ring110atFIG.4aand at collapsed mode of the expandable ring110atFIG.4b.

If necessary, the thrust shell100may be made rotatable within the TBM310's trailing shield312. For this case, connection between thrust cylinders150of TBM310and thrust ring160should be detachable (e.g. bolt, interlock, clamp or such connections) and thrust cylinders150should be retracted. There are different ways to rotate the thrust shell100. One simpler option may be using additional circumferential cylinders that can be attached to provisional lugs on the thrust ring160from one side which can be engaged with the trailing shield312provisional lugs from other side and then by extension or retraction of the mentioned circumferential cylinders, the thrust shell can be rotated.

Packer is recommended to be used on the leading circumferential side of the segmental rings172/174that will be in contact with the expandable ring110. A soft material (wood, stiff rubber or such) also can be attached to the expandable ring110surface that will be in contact with the leading side of the segmental ring172for better distribution of the thrust pressure.

If necessary, thrust can170may be separated from thrust ring160as well. In this optional case thrust ring170will have contact with the thrust ring160surface during TBM310pushing and advancing. However, some means of connection will be still necessary between thrust can170and thrust ring160for pulling out stage of the thrust can170from perimeter of the new segmental ring174. Several options can be considered for such connection. For instance, plurality of angles may be connected (bolted, welded, etc.) on thrust can170inner surface edge which can be paired with other angles connected (bolted, welded, etc.) on inner surface edge of the thrust ring160and then mentioned paired angles can have detachable connection (bolted, clamped, interlocked, etc.) together.

By detachable thrust ring160from the thrust can170, thrust can170can be made rotatable within TBM310's trailing shield312with almost similar way explained previously. For instance additional circumferential cylinders can be attached to provisional lugs on the thrust ring160from one side which can be engaged with the provisional lugs of the Can170from other side and then by extension or retraction of the mentioned circumferential cylinders between mentioned provisional lugs, the Can170can be rotated.

An alternative way to avoid using any Expandable ring110at the simultaneous tunnelling method by thrust shell system is that the precast segments may be modified in such a way that their outer perimeter trailing circumferential side has recess285to accommodate a circumferential plate280on the thrust can170to push on the segment as shown atFIG.5.

At this alternative, plurality of circumferential plates280will be connected to the Thrust shell's Can170by strong Hinges270. At the recess285areas of the segments, the mounted springs290on the Can170will retract the circ. plates280to the perpendicular position to the Can170by help of the Stoppers300at the edge of the Can170and so the Can170can push against the previously installed segmental ring172. After completion of the pushing cycle for one ring and after completion of installation of the new segmental lining174within the Can170, The Can170will be pulled back and circ. plates280will be rotated while contacting with the recess285's sloped area and may move along the Can170within gap between TBM310's trailing shield312and newly installed segmental lining174.

In other words, in this case the thrust can170of the thrust shell100will have plurality of segmented circumferential plates280at its end that are connected to the Can170by strong hinges270and will be able to rotate and contact with the previously installed segmental lining to push TBM310forward. The hinged circ. plates280will have springs290and stopper300, as shown atFIG.5and zoomed details atFIG.5a, that will hold the plate at vertical position unless thrust can170will be pulled toward the TBM310's mining direction which at this condition, the springs290will be extended and thus circumferential plates280will be almost at horizontal position and will be able to pass within gap between segmental ring174and trailing shield312. Tiny hydraulic cylinders/jack may be used instead of springs290at this case. The recess285areas of the segments will be filled by TBM310's lining grouting automatically. The hinge270may have a design that would be able to control and stop the plates280at their vertical position without any need for the stoppers300.

As an option, an attached inflatable ring may be utilized instead of circ. plate280(without stopper300or springs290) which will be inflated during TBM310thrusting and deflated TBM310re-gripping (during retraction of thrust cylinders150and pulling thrust shell100)

In many of the projects, the TBM310face pressure would be less than friction resistance created between TBM310shields and soil around it and therefore most likely the TBM310is not expected to be able to move backward at the moment of releasing the Expandable ring110at the proposed thrust shell100system (See stage atFIG.8e). Note that the TBM310should be prolonged to enable attaching the thrust shell100system, within its trail shield around 1.5 times of segment width (e.g. 2.25 m longer for 1.5 m width segments) which will help increasing friction resistance force too. In addition TBMs310usually have heavy-weight and thus friction resistance generated at bottom side of TBM310can be added to the friction estimation calculations as well . . . .

Further, the support pressure at chamber behind the cutterhead of EPB or Slurry TBM310to counter balance the face pressure might be taken into account as resistance force with consideration of securing the TBM310's gantry (which hydraulic pressure generator has been mounted) within previously built lining and thus making the mentioned support pressure as an external force against the face pressure.

If in some of the specific projects the friction resistance along with the support pressure is not sufficient to counter balance the face pressure of the TBM310, then below three methods/systems (a, b or c) may be considered to prevent TBM310moving backward at the moment of releasing the expandable ring110(see stage atFIG.8e):a) Using “Plough” system; Similar to older TBM310s, behind the cutterhead chamber couple of angled ploughs may be added which can be entered into the soil by their hydraulic rams just before releasing the expandable ring110which can prevent the TBM310moving backward. Then as soon as re-gripping completed at the thrust shell100system, the plough will be moved to their original position.b) Using “stabilizer”; The Stabilizer are used at newer TBM310swhich similarly can be used in proper sizes and nos. to hold the TBM310at soft soil against backward movement whenever necessary.c) Utilizing of the new Brake system called Thrust Shell-Brake (TS-brake322). At the end portion of the existing axle320of segment erector316(i.e. end portion of the existing fixed Frame/axle320of the segment erector316), a mobile ring323will be mounted which is able to rotate or move backward/forward or be locked on the mentioned axle/frame320(i.e. a separate mobile ring323on the existing axle320that is movable similar to segment erector316design). The mobile ring323will have couple of telescopic and foldable cylinders/rods324(let's say 4 locations with almost equal distances around the mobile ring323) to reduce their occupied space and obstruction which can be extended and entered into the concrete segment's existing lifting sockets326within the already installed segmental ring172. Then it can be locked and work as brake to prevent TBM310moving backward (and forward). If necessary, the fixed frame/axle320of the segment erector316may be slightly prolonged to accommodate the explained TS-Brake322system. See a TS-Brake concept atFIG.6.

The TS-brake can have different variations, for instance the telescopic rods324may be foldable to minimize their space while they are retracted. Also shoe plates may be added on the telescopic cylinders324that will touch and push to inner surface of the ring172without necessity to enter inside the lifting sockets326.

The new segmental Ring174and Thrust shell100and TBM's trailing shield312may be always parallel (even at curves), to prevent getting them stuck/jammed.

As shown atFIG.7, at an exaggerated very sharp curve new segmental ring174which is being erected within the Thrust Shell's Can170is kept parallel to the Can170by adjusting and simply less extension of jacks130and140at one side and more extension at other side for the tapered segmental ring174which has more width at one side and less width at other side in order to provide curve alignment at the lining.

So always expandable ring110and Thrust shell Can170will be contacting to the previously installed Ring172properly, even at curves, for appropriately pushing against the previously installed segmental ring172.

The rest of the concept at curve is very similar to the Conventional/Typical tunneling by TBMs. For example previously installed segmental ring172at the curved alignment will be located within TBM's brush318area and TBM's trailing shield312will be passing the curves in similar way of the conventional TBMs.

The thrust shell100system can be used at different tunnel cross sections e.g. circle, oval, square, rectangular, sub-rectangular and such. Regardless of any tunnel section shape, it would be necessary that Thrust shell100to follow tunnel cross section shape and be able to move backward or forward between trailing shield312of TBM310and Segmental lining172/174.

Stages Summary:

FIGS.8aand8billustrate stages A and B as following:

Stage-A: Ready to install Segments within Thrust Shell100and ready to push TBM310forward against previously installed ring172.

Stage-B: Segments of new Ring174are being installed by Segment Erector316(between jacks130mounted on Thrust Shell100and jacks140mounted on Expandable ring110), while TBM thrust cylinders150are pushing and advancing against previously installed ring via thrust shell100and via expandable ring110located front of the previously installed ring.

FIGS.8cand8dillustrate stages C and D as following:

Stage-C: TBM310is moved forward equal to width of the ring.

A ring has been completed by segment erector within thrust shell100, while TBM was advancing forward.

Stage-D: The mounted jacks140on the expandable ring110are being retracted and then expandable ring110is being collapsed.

FIGS.8eand8fillustrate stage E and F as following:

Stage-E: The collapsed expandable ring110will be lifted by Segment erector316to clear space between previously172and newly installed rings174.

Stage-F: The newly erected ring174is being pushed by jacks130mounted on the Thrust-shell100toward its final position contacting with the previously installed ring172.

FIGS.8gand8hillustrate stage G and H as following:

Stage-G: In the meantime Thrust shell100is pulled by TBM310's thrust cylinders150and expandable Ring110is pulled by Segment Erector316to its new position at leading side of the new erected segmental ring174.

Stage-H: The Expandable ring110is being expanded and positioned in front of the installed ring174and Thrust Shell100is being pushed to be contacted with the Expandable Ring110The mounted jacks140on the Expandable ring110are being expanded as well.
Stages: “A˜H” to be repeated for the next cycles.

Extra example of the thrust shell100system has been shown atFIGS.9,10.

The axial jacks130and140have not been shown for more clarity. Also previously installed segmental ring172atFIG.10has been shown as a simple ring (without lines showing boarders of the segments) to provide a simpler image.

FIG.9is showing thrust shell100and expandable ring110at a stage without contacting.

FIG.10is showing thrust shell100, expandable ring110and previously installed segmental lining172at a stage with contact and interaction at a 3d Finite Element Model (FEM).

ELEMENTS LIST

100 Thrust shell110 Expandable Ring120 Circumferential cylinders/jacks130 Axial mounted Jack of 100140 Axial mounted Jack of 110150 TBM's Thrust cylinder160 Thrust ring of 100170 Hollow can of 100172 Previously installed segmental Ring174 New installed (Being installed) Segmental Ring180 Stiffener of 160190 Sectors of 110200 struts on the Jack shoes210 lowest sector of 110220 upper sector of 110230 inner strip roller235 outer strip roller240 Telescopic beam250 Axial jack on 240260 Gap between sectors of 110270 Hinge280 Circumferential plate285 Recess of segment290 Spring300 Stopper310 Tunnel Boring Machine (TBM)312 Trailing Shield of TBM314 Stationary shield of TBM316 Segment Erector of TBM318 Brushes of TBM320 Axle (Frame) of 316322 TS-Brake concept323 Mobile ring of 322324 Telescopic cylinders (rods) 322326 Lifting socket of segments