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Boreholes and Rocks Layers

Starting in MiTS 2.7.12.0, users are now able to input another soil layer (‘rock layer’) in Earthwork. 

Note: need to define at least one soil layer at Parameter > Material > Soil Layer to continue

Steps; 

  1. Click ‘Soil Info’ and click once (anywhere at screen) to activate input mode 
  2. Input Borehole point details will pop up 

Note: 

Depth below surface – depth between ground level ( after minusing the top soil depth) to rock layer 

  1. Once all boreholes details are inputted, you may have something like below;

Why we need to separate the Rock Layers quantity #

Engineers sometimes need to excavate the rock layers during cut and fill in order to build the platform. The amount of cut for the rock layers and normal layers can be determined by utilizing this function. This is useful for QS because the prices for cutting rock layers and normal layers differ.

How to calculate rock quantity in Grid Method   #

Refer to ‘Grid Method’ chapter on how to use Grid Method to calculate Earthwork volume. 

Project file sample here

Note: the project file is modelled in MiTS 2.7.13.0 and get this version here

Layer condition Sample Calculation 
Platform Level higher than Rock Level (PL > RL) *NO rock volume since the excavation did not surpass the rock layer i.e Grid 198 
Let’s compare the PL and RL 
\begin{array} {|r|r|}\hline 0_0 & OGL (m) & Rock depth (m) & RL (m) & PL(m) \\ \hline 1 & 29.73 & 3.00 & 26.73 & 29.73 \\ \hline 2 & 29.00 & 3.00 & 6.00 & 29.00 \\ \hline 3 & 29.21 & 3.00 & 26.21 & 29.21 \\ \hline 4 & 29.98 & 3.00 & 26.68 & 28.76  \\ \hline \end{array}

From table above, all PL is higher than RL, hence NO rock volume
\begin{array} {|r|r|}\hline Point & OGL – PL (m) & Area (m2) & Volume (m3) \\ \hline 1 & 29.73 – 29.73 = 0 & 625 & 0 \\ \hline 2 & 29.00 – 29.00 = 0 & 625 & 0 \\ \hline 3 & 29.21 – 29.21 = 0 & 625 & 0 \\ \hline 4 & 29.98 – 28.76 = 1.22 & 625 & 762.5 \\ \hline & & Total Average Volume & 190.625 \\ \hline \end{array}
Rock Level higher than Platform Level (RL > PL)*in this situation, there will be 2 two (2) volumes; normal layer volume and rock volume i.e Grid 183 
Let’s compare the PL and RL 
\begin{array} {|r|r|}\hline & OGL (m) & Rock depth (m) & RL (m) & PL (m) \\ \hline 1 & 30.71 & 2.99 & 27.72 & 29.90 \\ \hline 2 & 30.08 & 2.99 & 27.09 & 30.08 \\ \hline 3 & 30.58 & 2.99 & 27.59 & 25.50 \\ \hline 4 & 30.94 & 2.99 & 27.95 & 30.30 \\ \hline \end{array}

From the table above, at point No 3, RL is higher than PL hence there will be two (2) volume; normal layer and rock layer volume

\begin{array} {|r|r|}\hline Point & OGL – PL (m) & Area (m2) & Volume (m3) \\ \hline 1 & 30.71 – 29.90 = 0.81 & 625 & 506.25 \\ \hline 2 & 30.08 – 30.08 = 0.00 & 625 & 0 \\ \hline 3.a & 30.58 – 27.59 = 2.99 & 625 & 1,868.75 \\ \hline 3.b & 27.59 – 25.50 = 2.09 & 625 & 1,306.25 \\ \hline 4 & 30.94 – 30.30 = 0.64 & 625 & 400 \\ \hline & & Total Average Volume Normal Layer (include 3.a) & 693.75 \\ \hline & & Total Average Volume Rock Layer(include 3.b) & 326.56 \\ \hline \end{array}
Note: 
– grid volume was calculated on point basis average 
– Original Ground Level (OGL); Platform Level (PL); Rock Level (RL)

Soil Profile Interpolation Method  #

To change the soil profile interpolation method, 

go to Options > Project Parameters > Earthworks > Material > Soil Profile 

  1. From Borehole group only 

Interpolate from existing borehole group profile only 

This ‘From Borehole Group only’ interpolation method will only use the BH soil profile information (use nearest rock depth below ground level) when generating the soil profile mesh. 

As image below, it can be seen that the rock level is referring to BH 4 soils information; 

  1. From Borehole group to with far field soil profile 

If you know what the soil profiles are, at a distance sufficiently far from the defined boreholes ( boreholes are expensive to drill after all, so their numbers might be scarce), then you can set this option and input the soil profiles.  Once this option is set, then the outest points of the available soil profile will have the defined characteristics set in the parameter Material->Far field Soil Info. 

The soil profile characteristics will be the interpolation between existing profile group and the defined far field soil profile accordingly.

Go to Options > Project Parameters > Earthworks > Material > Far field soil profile 

Note; 

  • Rock quantity only available in Grid Method 
  • For DTM and End Area will be implement in future versions 
  • Earthwork cut section only available for normal layer not including rock layer (will be implement in future version) 
  • Far field soil profile is referring to a constant rock depth defined (at far field) in the parameter setting in order to allow software to generate the soil profile meshing.

You may also refer to our latest video on ‘Soil Profile Layer in 3D View’ for further reference.

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