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[sono]

Hi,

I just noticed that my acquifier cavein project as by

http://dwarffortresswiki.net/images/c/c6/Aquifier_cavein_2level.jpg

failed to collapse. The layout is EXACTLY as in STEP 3 in the image series, that is supposed to collapse in STEP 4.

The circle is hanging in thin air.

EDIT: removed wall to no effect.

Code: [Select]


o = open space
x = intact soil/aquifier layer
t = tunneled
~ = water

z-1:

ooooooooo
oxxxxxxxo
oxoooooxo
oxoxxxoxo
oxoxxxoxo
oxoxxxoxo
oxoooooxo
oxxxxxxxo
ooooooooo

z-2

ooooooooo
ottttttto
otoooooto
otoxxxoto
otoxxxoto
otoxxxoto
otoooooto
ottttttto
ooooooooo

z-3

xxxxxxxxx
x~~~~~~~x
x~xxxxx~x
x~xxxxx~x
x~xxxxx~x
x~xxxxx~x
x~xxxxx~x
x~~~~~~~x
xxxxxxxxx



Halp?

[Kanddak]

If the wall connects the circle to a supported part of the map, yes it will prevent collapses.
Either your circle still has some kind of connection which you'll need to find and disconnect, or you turned cave-ins off in your init file.

[sono]

I have verified that neither is the case. It's a floating, gravity-defying monstrosity.

[Sphalerite]

Did you turn off cave-ins in your init?

I can also day from experience that the cavein method described in that image doesn't work.  Ramps don't block fluid, so carving the walls to ramps in step 8 will re-flood the pit.

[sono]

I did not turn caveins off... I guess you can still access it with a construction if ramps don't work. Thanks. Anyway, at the moment i still stare at this completely flumoxxed.

Here is the region savegame:
http://stashbox.org/736428/region1.zip

[Sphalerite]

What's on layer zero?  Do you have any floors bridging the gaps?

Can't build constructions downwards.  You might be able to drop a dwarf into the open space somehow and have him build up from there.

[sono]

There is nothing on z-0

Doh..

Well if i pump the water out i can afford building a single ramp i guess.

This is much more complicated than i anticipated.

[Sphalerite]

The useful thing to remember when cutting through aquifers is that smoothing walls stops water from coming out.  That's no help with soil layers, but if you're drilling through a multi-layer aquifer in conglomerate or similar water-laden stone, you can set up pumps to remove enough water for a dwarf to get in there and smooth the walls to cut the water off.

[sono]

Thanks.

I believe i have spotted the problem, even though i do not understand it. The ring seems to be hanging on tunneled out floors. That actually makes sense. Yes. I am sure it does.
By Armok.


I guess i need contructed ramps to actually do this method.. since i can't tunnel 2 Z layers deep without some way to get down and back up, and i can't compromise the ring that is supposed to collapse (and then isolate) so i can't get back out

Nowait, i can build an up/down stair in the very center of the spot and do the rest with floors.. nowait wrong again.

If i had known this would be so complicated i would have just settled for a lot of pumps and walls. I would be done by now. =p

Damn, i figured it out. I'll give it a go.

tunnel the inner moat first, by means of ramps/remove ramps. When you are on the bottom above the aquifier, mine the 3-wide ring underneath. Now you can build a stair outside of the rings and tunnel the outer moat. as soon as you are done tunnelling the outer moat, the collapse will occur.
at least i hope.

The wiki articles on this subject are terrible.

[Crowbar]

I'm currently having the same problem.  There is absolutely nothing supporting this chunk of rock, yet hang it does.  There's a dwarf on it, but that shouldn't be stopping it.  Should it?

This is my first aquifer.  Have I done something wrong?

EDIT: There is a TREE growing in the OPEN SPACE which I channeled to make the ring fall down!  I...I just...

[Amalgam]

Sounds like you're new to me. Punching through aquifers is hella hard for a newbie, you have to understand building support, cave-ins, water, aquifer dynamics, and machinery if you're using the pump method. I'm not even that new to DF and I was having trouble with an aquifer the other day because I've only done it a couple times.

The cave-in method is probably the easiest way to do this, if you're doing it that way I recommend you use supports for controlled cave-ins. The dust from cave-ins can knock miners and other dwarves into the water, so you should clear all dwarves out of the area when you do this. Creating a floor hanging over the pit you want to plug up and building a support there to hold up the section of earth you're dropping in should be sufficient. Cave-ins crash straight through floors so you don't have to worry about it blocking it.

[Huin]

My preferred technique to pierce a single-level aquifer is to carve out the following:

Code: [Select]

. = cave floor/ground
# = natural cave wall
_ = channeled open space
~ = water on aquifer level
> = down staircase
X = up/down staircase
< = up staircase

z-0:

...........
..._______.
..._....._.
..._....._.
.>......._.
..._....._.
..._....._.
..._______.
...........

z-1: (any level above z-2 and below the surface)

###########
###_______#
###_#####_#
###_#####_#
#X._#####_#
###_#####_#
###_#####_#
###_______#
###########

z-2: (level above aquifer)

###########
###.......#
###._____.#
###._____.#
#<.._____.#
###._____.#
###._____.#
###.......#
###########

z-3: (aquifer level)

###########
###########
####~~~~~##
####~~~~~##
####~~~~~##
####~~~~~##
####~~~~~##
###########
###########

The staircases are present so that each level can be accessed and carved out as described (i.e miner access).

Once I've carved out the above arrangement then I channel the single remaining floor tile from the surface layer to complete the channeled ring. Once the block of natural rock drops into the aquifer there is sufficient space to dig a 3×3 staircase downwards through the aquifer layer (if you dig through the middle 3×3 tiles in the dropped rock).

Miners naturally mine from the west of the tile they are mining, so this last floor tile will be removed by a miner *not* standing on the bit of ground that's about to drop. Sometimes the miner will get stunned by the ground falling next to him, or fall in - so it's not without risk. As far as piercing the aquifer is concerned, however, it works every time for me.

[sono]

I did it. I will probably update the wiki articles on the subject, since you have to do this in very specific ways for it to go through without madenning trouble.
Once it's figured out, it's almost trivial =)

note, this is not proofread and subject to revision, tho the concepts and instructions are verified.

this is all based on http://dwarffortresswiki.net/index.php/Aquifier#The_cave-in_method which you must read. or else. note that the wiki articles have at least one flaw in the design, as noted by other posters above, so stick to this. but still.

note, this is a guide on how to penetrate an aquifier with two topsoil and two water layers the dwarven way without excessive  use of walls and pumps (the human way). you will still need some, unless you are prepared to slightly modify the plans and wait for evaporation, or use a lot of buckets. in that case you can do it without any construction at all, even the supports can be planned around (anyone want to try this in hermit mode, feel free).  this is left as an exercise to the reader. first-timers are advised to read carefully and follow the guide exactly.

step 1, planning)

plan for almost a year to completion (if you do this for the first time, better plan for 1 1/2) before you can strike the  first rock. go into hobbit mode. bring enough stone (5-8 will do for anything you need in most situations) and one of every  kind of metal bar, seeds, turtles, silks, pets etc on embark, as someone is bound to go fey sooner or later.
leave out the anvil - you will get one in autumn, and until then you will have to be a dirtdwelling hobbit commune anyway (which is a great teacher for microing). you must be careful not to accidentally use your stone and metal for buildings you can as well make of wood. bring pets, carpenters, leatherworkers, bonecrafters, farmers - whatever you like - just go hobbit, live off the land and your crops and plan for moods. leaving out the anvil is acceptable, as the caravan is very likely to bring one or three in autumn (never had it not happen when i had none).


step 1a) the digging site

now select a square that is large enough to contain your vertical entrance shaft/ramp in whatever layout you prefer,  whereever your prefer, on flat ground. (i build 3x1 ramps for the main route with 2 2x2 stairs next to them as quickseal "wehrgang" and to ensure my outside workers dont have to run the defense maze every time, so i need at least 5x3 or so)
plan big and well, since this will be your only way down.

now expand the area that you will need to do any digging in by +2 in X and Y dimensions. this is the center square inside of  which you will eventually build your shaft. build a 1 tile wide moat around it.

note: do all your moat digging with ramps, never channel. this not only prevents unexpected results but will allow your  dwarfs to reliable dig further down, which they will have to do. (you may break this rule at your own discretion and risk.)

sketch out/designate the digs.

Code: [Select]

An example.

^ = ramp (planned)
s = stairs (planned)
x = any soil tile
z-1
^^^^^^^^^^
^xxxxxxxx^
^xxxxxxxx^
^xxssx^xx^
^xxxxx^xx^
^xxssx^xx^
^xxxxxxxx^
^xxxxxxxx^
^^^^^^^^^^

note the 2 tile distance between any planned digs and the moat.


now you will need another 2-tile ring around this moat, around which you will build another moat, and then your digging  support structures towards the north. (the north is for convenience so your dwarfs will not stand on the wrong tiles all the  time)

the aquifier z-levels have to be constant in the surrounding area or this will be more complex still, so make sure no heightmap changes are in the immediate area, or make test digs beforehand.

also plan for an entranceway on z-1 to the left or the right or south (you will see later.)

sketch out/designate the moats (remove your shaft sketches)

Code: [Select]

An example.


^ = ramp (planned)
x = any soil tile
z-1
^^^^^^^^^^^^^^^^
^xxxxxxxxxxxxxx^
^xxxxxxxxxxxxxx^
^xx^^^^^^^^^^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^xxxxxxxx^xx^
^xx^^^^^^^^^^xx^
^xxxxxxxxxxxxxx^
^xxxxxxxxxxxxxx^
^^^^^^^^^^^^^^^^


now you will need to think about access.

you will need three things:
I) an up/down stairs next to the outer moat to allow your miners to get back out later.

II) a safety fuse, namely either a lever (tho i wouldn't waste stone) or a small moat to cross the dangerous distance with floating constructions. note that we are planning a comparatively huge cavein which can affect your dwarfs at ~ 5 tiles  still.

III) a tunnel on z-1 to pump out water, which will later can become our access tunnel/ramp into the artificial doline, if you so desire. use your creativity on this one. if you wish to use a windmill for one or both of the required pumps (recommended,  see below) you must take care that a windmill is buildable above this tunnel or use a lot of mechanisms - hope you brought  the stone.

Code: [Select]

An example.

^ = ramp (planned)
x = any soil tile
s = stairs (as deep as you can before hitting water) mining access during construction.
_ = channel (h) (cavein fuse)
f = freefloating floors from above (cavein fuse, planned, sketched out for clarification), !!!those are actually built on  z-0!!!
t = tunnel (d) (pumpout, makes for a cool underground gate tunnel to your fortress entrance later)
w = windmill shaft from above (planned, sketched out for clarification)

z-1
xxxxxxxxxxxxxx
xxxxxxxx_f_xxx
xxxxxxxx_f_xxx
xxxxxxxx_f_xsx
xxxxx^^^^f^^^^...
xxxxx^xxxxxxxx
xxxxx^xxxxxxxx
xxxxx^xx^^^^^^
xxxxx^xx^xxxxx
xxxxx^xx^xxxxx
xxxxx^xx^xxxxx
ttttt^xx^xxxxx
tttwt^xx^xxxxx
ttttt^xx^xxxxx
xxxxx^xx^xxxxx...
,,,


step 1b) going under


you will build the moats two z-levels deep, then you will undermine the outer ring completely until it only hangs on your  constructed floor fuse for support. your miners will dig themselves 2 z-levels deep and exit via the stairs to the north.

{insert more longwinded description here}

Code: [Select]

An example.

^ = ramp (planned)
t = tunnel
x = any soil tile
s = stairs (as deep as you can before hitting water) mining access during construction.

z-2
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxsx
xxxxx^^^^^^^^^...
xxxxx^tttttttt
xxxxx^tttttttt
xxxxx^tt^^^^^^
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx
xxxxx^tt^xxxxx...
,,,


z-3 contains the first aquifier level.



step 2) the dig

start digging. you should dig the moats by means of ramps to two z-levels down, finishing one z-level entirely before you  start removing ramps on the one below. dig the stairs, and access tunnel/drain.
you should have built the fuse by the time you finish else there will be great fun to be had.

you will have to watch out a bit for your miners during this time, for they might idle and get stuck. do not worry, just keep digging. you can start with the outer ring, dig to z-2, leave via the access stairway, enter the inner moat, finish the inner moat, finish the undermining, and leave via the access stairway.

once your miners have reached z-1 and finished one or both of the moats, start undermining the entire outer ring. do not  forget to have the support securely in place.

Code: [Select]

An example (finished dig)


z-0
x = grass etc
f = floor tile
_ = open space
s = down stairs
xxxxxxxxxxxxxx
xxxxxxxx_f_xxx
xxxxxxxx_f_xxx
xxxxxxxx_f_xsx
xxxxx____f____...
xxxxx_xxxxxxxx
xxxxx_xxxxxxxx
xxxxx_xx______
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx...


z-1
x = soil layer
_ = püem süace
s = up/down stairs
t = tunnel
xxxxxxxxxxxxxx
xxxxxxxx___xxx
xxxxxxxx___xxx
xxxxxxxx___xsx
xxxxx_________...
xxxxx_xxxxxxxx
xxxxx_xxxxxxxx
xxxxx_xx______
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
xxxxx_xx_xxxxx
ttttt_xx_xxxxx
ttttt_xx_xxxxx
ttttt_xx_xxxxx
xxxxx_xx_xxxxx...


z-2
x = soil layer
_ = püem süace
s = up/down stairs
t = tunnel
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxsx
xxxxx_________...
xxxxx_tttttttt
xxxxx_tttttttt
xxxxx_tt______
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx
xxxxx_tt_xxxxx...


note: you need the ring and the outer 2 spaces of the inner slab intact under all circumstances. do not compromise them in  any way.


step 2b) removing the aquifier layer


dig a 2-tile wide channel - use channel (h), not ramps, here - directly overlapping the outer ring, where you tunnelled  previously. dig the inner strip moat first and make sure your miners exit before completing it and digging the outer strip.

Code: [Select]

An example (finished dig)


z-2
x = soil layer
_ = püem süace
s = up/down stairs
t = tunnel
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxsx
xxxxx_________...
xxxxx_________
xxxxx_________
xxxxx_________
xxxxx____xxxxx
xxxxx____xxxxx
xxxxx____xxxxx
xxxxx____xxxxx
xxxxx____xxxxx
xxxxx____xxxxx
xxxxx____xxxxx...


z-3
x = soil layer
~ = channel filled with water
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx
xxxxxxxxxxxxxx...
xxxxxx~~~~~~~~
xxxxxx~~~~~~~~
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx
xxxxxx~~xxxxxx...


note: do not trap your miners in the inner ring or you will have NO way to get them out without screwing the project up  hugely.


congratulations: phase 1 is complete and you can start the fun.

go up, activate and line up your dwarves for the show (and steam), and tell one miner to remove the last block holding the floors in place:

xx_xx
x_f_x

-> boomsplat.

the outer ring has collapsed INTO the water-filled aquifier channel. now you need to pump this water out before digging can continue: if you placed the windmill as designated above, you can build a pump right under it - no machinery required. you will have to build some walls too and a second pump on the level below, which can be operated manually - it will only be needed briefly anyway.

phase 2:

i am writing this in compressed form because if you got this far, you will have understood the basic idea. plus, i really don't have the time anymore, i will come back and expand and wikify this later, however.

pump out any water that splashed out to z-2 from the moat on z-3 if needed. the collapsed, two-tile wide ring will isolate the aquifier when we are digging further down.

this involves arranging a second cavein. notice how the central slab is still standing like a pillar? build floors again to link it to the edge securely.

when you have pumped out the water and secured the pillar, undermine the central pillar completely with tunnels.

now, build channels (h) _ under the entire central pillar +1 xy where your old inner moat was, effectively removing any remaining leaky, original aquifier stone inside the outer ring on z-3. take care not to drown your miners (they are bloody stupid and will happily dig away the stone under them).

now, you need the second pump. pump out the entire water that has accumulated during digging out the huge pool on z-3. no new water will leak in, since all aquifier stone has been removed. if it does, something is wrong.

you can build upwards ramps with the entire INNER tiles of the ring - this is, in fact, the reason we used a two-tile wide ring - but do never, ever, penetrate the outer tiles.

when you have finished pumping out the water, dig channels in the middle again: this time, an exact match for the slab above to collapse into. it will fill with water from the second layer of the aquifier, which you do not have to pump out.

collapse the pillar into the water on z-4. (big show)

now you can pump out any water that splashed out, remove the pumps - they will no longer be needed - and design the entrance to your wishes. keep in mind where your insulation starts and ends, and do not dig out the outer slabs of your insulation.

[eerr]

bridges, grates, and a few other pathable constructions won't hold weight, so you may efficiently use them to path onto cave-in designated constructions.


Floors, pillars, walls, ramps and stairs of any type can hold up infinite weight.
They are heavyweights, because they have infinite weight-lifing power.
Objects held include Stone, walls, and anything else you could possibly place on them. (a whole dwarf fortress hanging from a single chalk pillar, or a whole mountain if you prefer)

Touching corners don't hold weight, only edges and the side of walls.

Walls can hold weight with any side they share (any edge as well).
 Any floor edge with a stairs, floor, wall top, wall bottom, or ramp top.
Any ramp holds weight if built with one side sharing it's face with a wall, or touching it's bottom edge with a wall.
Any pillars hold the floor(wall) above, and the floor(wall) below together.
Stairs on top of stairs will hold up  (one?) other stairs, but won't hold up floors or walls alone.

Other constructions like bridges, hatches, grates, floor bars(made with (b)) doors, floodgates don't hold weight heavyweights, no matter what edge is connected.
Bridges might be able to hold up Bridges though, I'm not sure. Building a floor off a bridge is a major source of cause cave-ins.

I'm not sure about mechanisms, but one mechanical device can hold up a connected mechanical device in a similar fasion. Beware that turning off a mechanism with a lever may deconstruct it, removing support.


Starting from the ground, if a heavyweight shares an edge with another floor , wall, ramp or stairs, it can hold infinite weight.
Except for the link between two stairs, as there isn't a straight edge between them.

Cave-ins of natural rock walls will squish all natural walls between it and the bedrock floor, flattening all space and objects between them. Like dropping a giant rock cube onto another rock cube. Other objects between them are almost ignored.
Constructed walls and anything else are either annihilated,or can be dug out from the wall. I'm not too sure on the details.

Cave-ins of other objects will destroy anything lighter than a natural wall or constructed wall that they fall upon.

[Sphalerite]

Actually, cave-ins of natural rock walls won't destroy natural or constructed walls they fall on, although natural or constructed walls can be left entombed in the solid rock once it finishes falling.  Constructed walls collapsing will deconstruct to blocks, but only after they finish falling - they'll punch through floors on the way down.

And stairs will support any number of stairs, floors, or walls.  Ramps don't support anything, as many miners have found out the hard way.

Bridges can hold up other bridges, but nothing else.  You can also end up with bridges floating in midair if you retract them and then deconstruct what was used to support them.