Efforts to use OneDrive to post a photo to give a sense of the project opened a pathway to my entire family photo album (fascinating, I am sure, but a bit beyond the subject matter!), so I am going to have to try and describe this project with words.
The garden settled about 2" along a 48" length of track that more or less abutts the garden’s retaining wall. The finished project will thus only be visible from one side and, of course, from the top.
From a practical standpoint, I just need to get the rails level. From a visual standpoint, I want to take advantage of, rather than fight, some of the undulations in elevation from settling over the last 2 1/2 years. I want it to be solid enough to allow for adjustments as things continue to shift about, and I want to use the project as an excuse to dicker with some other tools and techniques.
My thought was to use a hardiebacker sub-roadbed (snapped to size using a score-and-snap technique I recently learned about) mounted on some sort of core. I had thought about foam, sealed behind latex paint, for the core which would keep the weight down and make it easier to adjust as required. I would then glue foam to the side and score witha hot knife for texture. I can also use something more substantive like bricks for the core if this would be better. Thoughts?
I am also mulling scrapping the whole retaining wall idea and, instead, building a bridge and leveling out the garden bed underneath. This would be something simple, using some techniques Tom shared in another one of my posts. It would accomplish the same thing, I think, but I am not sure how it would look.
As ever, I would appreciate any “guidance to the helm!”
Ground subsidence will be an issue for several more years. You say you have about 2 inches of subsidence in 2 1/2 years. In another 2~3 years you should expect another inch to 1 1/2 inch more subsidence, and so on over the next dozen or so years. Be prepared to repeat whatever you do this season in a few more years. The quick fix would be to get a 5 gallon bucket of crusher fines. Pile up a bunch between the rails followed by vertically shaking the track allowing the fines to settle under the ties. Repeat as needed to raise the track to the desired level. Add this task to your yearly late spring time to do list. I say late spring due to my experience, most of my subsidence (yes, I still fight subsidence after 17+ years) occurs during winter/ early spring.
You also stated you want to experiment and develop more skills, while keeping the uneven natural low areas for the visual effect. A 48 inch long, 2~3 inch tall bridge will be a great visual enhancement. If you go with a timber trestle bridge be prepared for annual maintenance. As the ground under the bridge continues to subside some posts will lift out of the ground while others will drop along with the soil. A through truss bridge set atop concrete piers might be a better choice, but MUCH more work. Build a wooden form to make a series of identical piers that reach down 5~6 inches below current ground level. You could experiment with making a rubber mold to make the piers. These piers would need to be supported by a structure that reaches down to at least 3~5 inches below the original grass level from before you built the GRR. Just a
Photo sharing. Most of the older sites we have used over the years have begun shutting off ‘third party’ photo sharing. I just got a message from Photobucket that ‘third party’ sharing will quickly end unless I spend more money to keep that feature. Not so willing to pay the added fees.
Tom, lots to mull over…To be clear, do I have to dig down below the grass, or just into the raised bed? The GRR is about 2’ off the ground, with the first 20" dirt, and the rest gravel to the top, except where our plantings have gone in. In the meantime, I have a few other repairs I am doing as I chew this over. Oh, yeah, I also refuse to pay the Photobucket fee. Not sure what to do now for photo sharing. Enjoy your weekend! Eric
In order to completely defeat subsidence of track right of way one must go below the lowest known layer of decomposing green matter. Not knowing how much green matter is in your fill soil, I’m sure there is some, possibly up to 15~20%. If I recall correctly your buried your lawn under the empire. Look at a cross section of the average lawn. Below the grass line is the root zone 2 to 2 1/2 inches deep. Below that is a zone of decomposing older roots, another 2 or so inches. If your intent is to totally defeat subsidence you will need to go at least 6 inches below the grass line for support.
You are fighting two types of subsidence. First being the decomposition of green matter which depending upon the type of green matter, water content and aeration takes 6 to 10 years, possibly longer. Secondly, you have normal soil compaction, which will continue for a few hundred thousand years until it turns to rock. Even if you were to dig two feet below the grass line you will still experience subsidence in the neighborhood of a quarter inch per ten years. Subsidence is just something we learn to live with. Don’t get too depressed and think all is lost. If you decide to go with a truss type bridge with cement piers reaching down about 5 inches or so into your fill soil your subsidence rate should drop to 1/4 inch or so per year. If the piers drop completely vertically all you would need to do would be to use timbers (wood shims) to level out the bridge every couple years. Every year the rate of subsidence will get a bit less and less.
My new “still under construction” empire is experiencing subsidence. 4 years ago I built a 4 foot retaining wall and put in about 36 inches of decomposed granite. Every year since I’ve hired local day laborers to add another 5 yards of DG about 2 inches. As it continues to compact by age the level gets a bit lower each year. A broken hip and couple surgeries have slowed construction a bit. I had it at 12 inches f
Photobucket, like other photo sharing sites is a business. Over the years I have had them make me some oversized prints of some of my photos, as a way of paying for their service. I already pay for two cloud storage sites and am not interested in paying for another.
An after thought. You are currently concerned about one small section. How is the rest of your track doing? Look close, I’m sure you might find some settlement in other older areas with lesser subsidence.
For the moment, one section. I had some slight settling elsewhere, but I just backfilled the whole area based on future plans of what I wanted to to in those spots.
In this area, our little guppy pond is in the center. Along one side, I shored things up with broken concrete slabs, glued scale timbers to it, and called it a day. Along another, I used a line of scale “boulders” to serve as a wall wall to hold up the gravel fill. I nice grove of blue daze effectively does the same thing on the third side. This side is the longest run of track, so I thought something a bit more permanent would be in order. Been working on what that would be all afternoon and evening.
There is an overhead shot in my build log "Progress on the Triple " to orient yourself. Oh, and issues with any site making its fair profit; I just am already paying for one site, and I have too many log-ins to remember as it is!
Thanks again for you very in depth answers. Since the trains run fine, I am going to take a real stock of my options and resources before committing to any one course of action.
Tom, As I chew on all this, I think I am going to have to forgo the bridge idea. Realistic assessment of available time indicates this would take trains out of operation for months. Also, as there is at least a theoretical plan to turn our guppy pond into a proper water feature, a project of this nature could be premature. I like the culvert-and-wings suggestion. This seems more flexible over the long term, and more repeatable when required elsewhere along the line. And, it should allow for the development of modeling skills, albeit in smaller and more likely to be accomplished chunks! OK, enough theorizing…The sun is hitting the crest of the Ko’olaus, and it is time to get a train or two running in Olomana’s shadow! Aloha, Eric
Allegedly using the link from OneDrive will not give the world access to my family album; unfortunately, despite what their help desk said, that does not appear to be the case…
Anyway, I think the culvert approach will work best based on some internet searches, my available time, and my available tools and talent. As silly as it seems, I just couldn’t think of a good way to make the wings around the pipe. My tools include a good electric drill, my Dremel, a circular saw, and various gardening tools. Making a form into which I could pour concrete would be at the outer limit of my tools and capabilities, I would think. I was thinking of basically drilling into hollow tile, adding the pipe, the using construction glue to add a wooden top and wings. The theory being that I could always lift out the whole assembly, back fill the hole, and reposition it if I had to. Alternatively, what about timber cribbing? I could cut some timbers to standard sizes, stack them into squares or rectangles, and drill holes in the corners for a screw to hold the lot together. Then just backfill with the gravel and, hopefully, have a workable solution.
Anyway, hope this helps to frame the problem better. I’ll keep dickering with the photo link issue, and hopefully be better able to frame this issue soon!
Quick hint for culvert construction. Timber is quick, easy and commonly used. ‘Concrete’ (mortar mix); Build a multi use form. Use a piece of 1/2 inch or 3/4 inch plywood as a base. Drill a hole through the plywood very slightly larger than the diameter of the pipe you are using. Use 1/2 x 1/2 wood strips to make the outline of the header wall and wing walls. Lay the wood strips out to form the header wall, a rectangular shape of about 2 1/2 inches tall and 4 inches wide. The ‘pipe hole’ should be about 1/2 inch above the bottom of the headwall. WingWalls: 4 inches across the bottom, 2 1/2 inch tall on one side and 1 inch tall on the other side. CAUTION: wood will wick away the water in the motar mix too fast for the motar to properly set up. Use some GAA (grease automotive and aircraft) and coat the wood with a thin layer making sure to work it into the joints between the plywood and wood stips to fill any holes and gaps. Put a good coating in the pipe hole, but not on the pipe. Insert the pipe and fill with mortar mix, cover with wet paper towle and set aside for a day or two. Before inserting the pipe use some 40~60 grit sandpaper and spin the pipe to put some small grooving in the pipe. The grooves will help the motar mix to hold the pipe. I’ve had some problems using white lithium grease and prefer the regular stuff. The grease works well as a release agent when removing the walls from the forms. After the mortar has well setup, gently turn the form upside down and the pieces should fall out with ease. I usually break about 1 in 10 of my ‘walls’, just pour another as needed. Since wingwalls normally attach the the header wall at an angle there are two possible ways to attach. (1) Lay some coarse sandpaper on a flat surface and gently remove a little bit from the back corner so you get the angle you want. Glue the walls together with some adheseve or a bit of wet mortar. (2) Without sanding the edge, just position the wingwalls in place and fill the gap with mortar mix. If
Tom, No worries about the verbosity. Both approaches are within my skill and toolkit. I think the scored board will work in the longer area, solving the immediate problem, and the form is something I can hold in reserve for troubleshooting and spot repairs! Also, thanks for the OneDrive tip. It is late, so I will try to monkey with it again tomorrow. Aloha! Eric
Note I did have to use the “insert image button,” and I hope it does not lead to my whole OneDrive (Opening the picture on CINCHOUSE’s computer only led to her OneDrive). Anyhow…
Now you can see the degree of settling in terms of depth and length. As mentioned, I am going to use the scored board method here. Assuming this photo does not give everyone access to our family album, I’ll update this when I get underway with the project.
Only the one pic shows up. There is one thing a bit strange. Normally clicking on the pic opens it up in a new window. A click saves it to my hard drive. "Open in new tab, open in new window also saves to har drive. Strange.
HUZZAH!!! Semi-success! I had the same thing when I was working wiht this, that it would open and try to save the picture to my drive. As you said, strange…
Tom, Stain is on hand, and the hardware store has the appropriate bits of scrap wood. I am going to see if I can get the 1x6 for free this week before commencing OPERATION RETAINING wall. Likewise, all material on hand or sourced for the culverts, but, as concrete and mortar mix has a short half life in the tropics, I am going to hold on that technique, other than the mold, until I need the mix for a household repair…something that appears almost as fast as mortar mix fails in the tropics! Aloha, Eric
Scored a board, using the ties of my LGB track to size the lines. Figured I’d make the wall look like it was made of railroad ties. I did not score the bottom two inches, as the wood splintered when my father-in-law cut it down, it will be hidden, anways, and as it is a plywood, not solidwood, I doubt this wall will live to see the garden settle a full 6", anyway! I will see if I can get this stained over the week.
I also bough the material for the culverts and forms, so that I have the forms on hand for the next phase of the project, which will be to shore up some random places about the garden, possibly leading to some scenic developmeent as we go.
FYI, the concrete walls and wings are very similar to stream crossing points along the Oahu Rail & Land mainline my oldest daughter and I found up beyond Mokuleia, so I could see these forms doubling for some short, basic bridges, too. In 25-30 years, we may have a real representation of a Hawai’i sugar cane road after all!
Thanks again for the tips, and I will keep you posted with the progress!
Eric, Do you have access to volcano ash? If so, do like the Romans did, add 1 part ash to 4 parts mortar mix. Better yet, mix equal parts cement and ash. It beefs up the water resistance of cement. Some of their bridge piers poured under water are still in use to this day. The ash/cement mix is extra light and extra, extra strong. Rome has several domed buildings that have been standing for over two thousand years.