Rock Mechanics - Science topic

Could you please share some innovative project ideas or recent advancements in mining engineering? I'm particularly interested in areas like rock mechanics, blasting techniques, mine safety systems, and water management in mines. Your insights would be greatly appreciated! Thank you!

International Journal of Rock Mechanics and Mining Sciences(IJRMMS)

The paper was submitted on September 13, 2022， and was rejected on January 11, 2024.

During the 485 days review cycle, there was no response, no review or suggestions made on the content of the paper, and it was ultimately rejected as not meeting the scope of publication in the journal.

Several authors waited for 485 days, only to receive an unapologetic and irresponsible response below.

Dear Professor XXX, Thank you for submitting your manuscript to International Journal of Rock Mechanics and Mining Sciences. I regret to inform you that the reviewers recommend against publishing your manuscript, and I must therefore reject it. My comments, and any reviewer comments, are below. We appreciate you submitting your manuscript to International Journal of Rock Mechanics and Mining Sciences and thank you for giving us the opportunity to consider your work. Kind regards,   Professor XXXX XXXX Editor-in-Chief International Journal of Rock Mechanics and Mining Sciences Editor and Reviewer comments:   This manuscript is primarily focused on geophysical imaging and processing techniques and in my opinion is outside the scope of IJRMMS. The work presented is largely mathematical with little rock mechanics. My recommendation is to encourage the authors to transfer their manuscript to Elsevier's Journal of Applied Geophysics, where it is better suited both in terms of interests of the readership and securing knowledgeable reviewers.

International Journal of Rock Mechanics and Mining Sciences-IJRMMS

After 485 days of review, no comments were made on the content of the manuscript, and the manuscript was rejected only on the grounds that it did not meet the scope of the journal. Here are the only responses.

Dear Professor XXXXX,

Thank you for submitting your manuscript to International Journal of Rock Mechanics and Mining Sciences.

I regret to inform you that the reviewers recommend against publishing your manuscript, and I must therefore reject it. My comments, and any reviewer comments, are below.

We appreciate you submitting your manuscript to International Journal of Rock Mechanics and Mining Sciences and thank you for giving us the opportunity to consider your work.

Kind regards, Professor XXX XXXX Editor-in-Chief

International Journal of Rock Mechanics and Mining Sciences

Editor and Reviewer comments:

This manuscript is primarily focused on geophysical imaging and processing techniques and in my opinion is outside the scope of IJRMMS. The work presented is largely mathematical with little rock mechanics.

There is an underground powerhouse structure in the Himalayan region. In this structure, rockbolts and steel ribs were installed.

The rockbolts have load holding capacity of 57 tons but due to improper installation and poor rockmass condition, the final load-holding capacity of the rockbolt varies between 30 tons to 57 tons.

The load is increasing on the underground structure and at several locations, rockbolts are failing because the load reached 45 tons.

At the same time, steel rib has a compression capacity of 1.06 MN/m2 but at a few steel ribs, it has reached 1.33 MN/m2.

What are the geotechnical risks involved in such a situation in this underground rockmass structure?

What corrective measures would be necessary to handle such a situation in this underground rockmass structure?

Rock mechanics

I tried to find a site where I can buy a needle penetrometer for weak rocks/soft rocks. But my search was not successful. Does anybody where I can get a needle penetroemter? Links are welcome.

Compared to the old-fashioned and currently used emulsion type explosives, the explosive filling of the tunnel face with bulk charging provides better and higher quality vibration values. if you are drilling in the tunnel face with the Mwd (measurement while drilling) featured jumbo. Because with the mwd-capable machine, heterogeneous drilling is performed in the formation whose face surface is uneven and the drilling lengths are different. Therefore, a homogeneous charge in a heterogeneous face with an emulsion-type explosive of constant kilogram will be difficult. Therefore, I think that more stable vibration data will be obtained with bulk charging. What is your opinion?

Are you interested in reservoir characterization? Want to learn about tools that can be applied to oil & gas, critical minerals, and CCUS? Then consider participating in the Premier-Corex short course at the 2023 Rocky Mountain Section AAPG meeting in Bismarck this June. Can't make it to North Dakota? No problem! There's a virtual option. See below for details and links to the meeting registration site:

What: RMS-AAPG Premier Corex Short Course

When: June 4 (Sunday) 2023, 8 am to 5 pm

Where: Radisson Hotel Bismarck (room TBD); virtual component*

Sponsoring Organization(s): Premier-Corex; AAPG Rocky Mountain Section

Title: Applications of Reservoir Characterization Workflows to a Range of Geologic Energy Resources in Sedimentary Basins

Mike Dix (Premier Corex) - Geology and petrology

Jules Reed (Premier-Aberdeen) - Core analysis, special core analysis, flow studies in general

Sean Arrington (Premier-Houston) - Rock mechanics

Peter Johnson (Carbon Solutions) - Reactive transport and other modeling

Mike Dix (Premier Corex), Bryan Guzman (Premier Corex), Bret Fossum (UND-EERC), Tim Nesheim (NDGS), and Justin Birdwell (USGS)

Description: This 1-day course will provide a review of reservoir characterization workflows for sedimentary basins relevant to development of variety of different resources. A variety of topics will be covered, including (for details, visit: https://www.rms-aapg2023-bismarck.com/short-courses):

Who Should Attend: Geoscientists and engineers interested in reservoir characterization using core, cuttings, and other data types to develop conventional and unconventional oil & gas resources, carbon sequestration prospects, and critical elements/minerals in sedimentary basins.

Unconventional Resources (2 hours)

Conventional Resources (2 hours)

Critical Elements/Minerals (1.5 hours)

CCUS (2.5 hours)

Professionals: $200

Students: $50

Virtual Attendees: $125

*Note, virtual attendees may not be able to view all content due to use of proprietary data in some modules.

Includes: Handouts, presentations, Q&A: light breakfast and boxed lunches provided for in-person attendees

If one is monitoring an underground rockmass structure (underground powerhouse currently producing electricity) using microseismic monitoring process and there is no occurrence of earthquake, blasting, micro-earthquakes, transportation of material etc. in that region.

We are getting about 150 microseismic event in six month and the deformation is low.

Can we say that we are doing dynamic stability analysis of that underground structure using Microseismic monitoring? If yes why?

In order to calculate the volume of an in situ block intersected by three joint sets, besides spacings between joints, we also need the intersection angle between joint sets. How can we calculate the intersection angle between joint sets using dip and dip direction data? Can you recommend any methods, software, or papers related to this subject?

Rock Mechanic

Kindly suggest a recent review paper on developing landslide early warning system in Hard Rock Slopes? It would be great if papers are provided where role of rainfall is considered in rock slope. It is important to mention here that, I require papers where rainfall role in hard rock slopes is considered NOT soil slopes. Kindly suggest recent papers on this topic. Thanks

I would like to know what the minimum strength of a rock has to be when I want to conduct a point load test. When rocks or indurated soils have a strength below a certain treshold they fail very fast and the result of the point load test is not evaluable.

Rock in chemical solution will appear chemical damage, this damage is a kind of water-rock interaction, so we can expect rock mechanical properties cracking, what else can we pay attention to?

Hello everyone. I'm working on reservoir rock mechanical properties. Do you know any conducted study on correlation between rock mechanichanal and thermal properties?

I want to get information about world-class universities, especially in the fields of geotechnical engineering and tunneling. Therefore, the following questions arise:

Which universities and in what research topics are the best at present?

What are the reasons for choosing them?

Please share the links in your comments.

I am currently focusing on 3D geomechanical modeling. And in the future, I want to extend it to a 4D model. During my recent studies, I realized that most of the 4D geomechanical modeling that has been done has not properly updated the elastic properties such as Young's modulus, bulk modulus, Poisson ratio, etc. If a 3D static model is extended to a dynamic model, or a two-way or one-way coupling is performed, it is necessary to consider all material behaviors in a time-dependent manner. Please share if you have useful information in this regard or if you have a suggestion, I would be grateful if you could comment.

I have completed a Master of Engineering in Mining Engineering. I am currently exploring the possibility of pursuing a Ph.D. in the same domain in early 2022 or 2023.

My areas of interest are the following:

- Rock mechanics and ground control

- Backfilling the mined-out area

- Gemstones and their processing

- Open-pit optimization

Any other suggestion beyond this abovementioned is also welcome.

Thank you.

I am a master degree candidate in Mining Engineering. I am interested in rock mechanic and geotechnical area of study in mining, which will be highly in demand in the future. any suggestions would be appreciated.

Bit of background… Geotechnical engineering in mining focus on broader classification (RQD, Q, RMR etc). The makeup of rocks grouped in these classifications and other classes like lithology can vary significantly. For example, some data I’ve looked has a range of 40% iron content for an individual lithology. I would expect something like iron influence rock mass strength, an influence which would be masked if not lost, when relating the broader categories to excavation performance.

I am a Ph.D. candidate in Mining Engineering. I was so confused in the selection of a suitable topic for my Ph.D. My areas of interest include Slope Stability, Rock Mechanics, Rock Blasting, Slope Stability, Waste Management, and Environmental Management in Mines. any suggestions would be appreciated.

I am looking for the data from the completed Tunneling projects located all over the Nepal if possible. Data can be geological mapping, Physical features, rock mechanical data if any, tunnel convergence or any deformation related values, etc.

Can anyone direct me to the places or person that can help me in this process.

Thank you!!

What are the parameters required for designing open pit mines?

Hi everyone!

How we can calculate the stress intensity factor (KI and KII) in numerical software such as FLAC, UDEC or any software except Abacus (I mean Integral J)?

There are some equations for determining KI and KII based on stress in crack tip, but it cannot be calculate the KI and KII because of teta angle in these equations. Does any relationship between KI and KII based on stress in crack tip (for inclined crack)?

Thanks in advance for answering.

we have some experimental data of mechanical strength of rock material. We compare this data with the estimated strength (calculated using several existing criteria) and also determined the error percentage for each criteria. 

So i want to know that

what is the maximum percentage of error, that is acceptable for rock mechanics purposes, specially when we compare the experimental data with the estimated ones.

dear friends from the rock mechanics field

Good day. I have what may seem a minor problem, but I cannot crack it somehow.

I have attached a page from Hoek & Brown (1997) paper, which gives elaborate spreadsheet formulas for simulation of triaxial data and conversion to Mohr-Coulomb parameters, in absence of actual triaxial tests. All the formulas are explained and mutually connected except one.

What is the formula for signt??

It is the normal stress which must be specified in order to calculate the tangent to the Mohr envelope. There is a myriad of formulas involved with the problem and I just don't see the answer. I would greatly appreciate assistance.

Cheers, Hrvoje Vučemilovič

I did my PhD research on slaking rocks or soft sedimentary rocks, respectively. During my literature research in the beginning of my PhD project it was pretty obvious that there is no general defintion of the terms "soft rock", "weak rock" etc.

There are two fundamental views. On the one hand there are the (classic) defintions with respect to the strength of the rocks on the other hand there are defintions relating to the slaking behaviour of rock.

Even in the very recent book "Soft Rock Mechanics and Engineering" most of the reseachers find it necessary to define the term "soft rock" and how it is used in the following chapters indicating that there are still lots of open questions regarding a general definition of this/these group of geomaterial.

What is your opinion on the definition on the term "soft rock", "weak rock", "slaking rock" etc.?

Dear colleagues!

What is the best method to determine In SItu Block Size Distribution if I have orientation, spacing and persistence data collected from 3D Point Cloud?

I considered using 3DEC but I am not very fluent in the software.

trying to work on the problems a mine face due to watery strata, but couldn't find the appropriate matter for study.  

Hello everyone!

I'm looking for the most recent developments in analytical, numerical and experimental micromechanical modelling of mechanical and flow response of Jointed Rocks.

I would like this space to be open and free also to suggestions of materials, articles and so on.

Thanks a lot!

Augusto Borges

I am planning of furthering my career by doing a PhD in Mining engineering, most likely in 2021 or early 2022. My areas of interest are Rock Mechanics and mining geotechnical. I am not too sure about the topic that I chose. Is this topic still interesting enough for now?

or are there any suggestions for other topics that are more interesting?

as well as university recommendations for me to take my doctoral programe ?

There are three primary areas of ground movement towards a pressurised TBM: at the face, along the shield skin and at the tail void -(In the attached figure).

Can the maximum surface Settelment of the tunnel Longitudinal Cross section due to the displacement of the tunnel face can be added with the Transverse cross-section surface Settelment and introduced as the final surface Settelment? in 2D model-numerical method.?

But in the transverse two-dimensional method, we cannot get Settlements dou to face pressure induced by tunnel advanc.

I was going to get the Settlements dou to face pressure from the longitudinal 2D model and add it to the other Settlements Caused by other factors

In the longitudinal section of the tunnel, details and geometries and conditions have been implemented so that only the displacement caused by the face pressure is created and that the shield cone and mortar injection and consolidation are not modeled.

so only max surface settelment in longitudinal cross cestion is occurred due to face pressure It is capable of adding with max surface settelment in transverse cross sestion due to injection pressure and shield cone?

I simulated the shield driven-tunnel by FLAC 2D, in which step of numerical model must be applying the traffic loads of ground surface (20 Kpa)? the traffic loads of ground surface change along day and night

@steps:

1. elastic initial equilibrium.

2. elastic-plastic initial equilibrium.

3. Simultaneous with excavation and pre-installation lining.

*in which step influence the traffic loads is real? (interaction with ground above tunnel)

I need a large model say 100 x100 m with a mesh size of 0.05m. such a large model cannot be made in version 7. before upgrading to version 8, I need to confirm whether it is working in version 8 or not?

I have also tried trail version 8. it is also not working

if anyone has version 8, I can send you a file to check.

Thanks

When conducting analysis of foundation on rocks, and the triaxial test results of the rock material is found as c=3 MPa and ϕ= 44 degrees. In analysis, this cohesion value has to be reduced to account for the rock mass, to a value of maybe 50-300 kPa. Is this assumption correct? Or are there some correlations in the literature?

For saving money, petroleum industry prefer poroelastic equation to calculate minimum horizontal stress rather than direct measurement (e.g. via Leak-off tests). Still, by comparing the value of calculation and measurement, it is showed that the value from calculation always underestimate the one from measurement. This phenomena has been interpreted to be caused by tectonic strain. I determine the tectonic strain. And, I'm trying to find some implication of tectonic strain on petroleum processes, for instance, wellbore stability or sanding production potential.  

Residual soil is the product of the weathering processes for rocks.

What are the main characteristics of this residual soil?

Dear colleagues!

What is the best method to determine the spacing of the discontinuities on a digital 3D model of a rock slope obtained with TLS? I am only looking for a manual method since the aim of the Master thesis is to compare manual and semi-automatic methods.

Semi-automatic mapping results were obtained using DSE.

I want to measure the hardness of particles that are smaller than 120 micrometers. Do you think we can use depth sensing nano indentation method to measure the hardness of this material?

Can someone provide a manual or a guide of geotechnical investigation procedures for different types of constructions in English? I mean a guide of methodology and standard procedures for transmission towers, bridges, regular houses, etc?

I am interested in a manual which is compatible with Eurocodes or ASTM standards.

There are so many tunnel excavations, and so many who use either 'observational' (maybe double-shell) NATM or single-shell B + S(fr) selection from Q, or RMR, or less frequently RMi. Many then ask their younger (?) numerical modellers 'in the office' to check for 'plastic zone' size (often using the RocScience Hoek-Brown, GSI, Phase 2 / RS 2 software). We can alternatively use UDEC-MC or UDEC-BB to check for bolt and shotcrete loading. There are no 'plastic zones', just modelled joint adjustments: some joint shearing, joint aperture changes, and deformations. An altogether clearer idea of rock mechanics mechanisms. We can make improvements in bolt spacing or length or shotcrete thickness/strength if needed. Unfortunately it has been known for a long time that one should not add 'c' and sigma n tan(phi), either in linear Mohr-Coulomb or non-linear Hoek-Brown. This applies to the FEM continuum models. The nested equations involving a crudely estimated GSI (from a diagram, not from characterization) and the following opaque equations of c and phi need software as they are so complex. There is also a disturbance number D giving great freedom for the result, and a deformation modulus equation without depth or stress adjustment. Unfortunately the 'plastic zones' that the young modellers produce, though very colourful, may be grossly exaggerated, as found in a formal court case concerning a stable tunnel excavated without the need for shotcrete support. Is it not time to re-think the numerical modelling we are often doing in rock engineering? It is often based on so many a priori assumptions with even the input needing software. Mostly, the empirical methods, though with some inevitable weakness like subjectivity, are at least based on a posteriori principles.

I'm searching for open access and peer reviewed international journal (obviously of high quality and with Impact Factor) to publish research on geology, geomorphology, landslides, geotechnics, soil and rock mechanics.

For RMR and SMR classifications, field work is required to obtain information about discontinuity dip, strike and ,.... Are are aware of any resource to learn this field work?

From Wikipedia

”In engineering, a foundation is the element of a structure which connects it to the ground, and transfers loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics(Geotechnical engineering) in the design of foundation elements of structures.

I was simulated 500 kg TNT on the ground surface to explosion, soil is clayey sand with young modulus E=100 MPa, dimensions of ground crater due to detonation is 70 cm in depth and 200 cm length!!(according to figure)

Are the results of the sizes correct??

I simulated one tunnel in the soil medium, I going to study on the ground surface settelment due to excavation tunnels

Which Constitutive model of the soils (SC-GC) is better? and why?

1. Mohr coulumb (MC)

2. Soft soil

3. Softening strain (SS)

4. Hardening soil (HS)

5.Hardening soil small-stiffness (HS-SS)

6. CY-Soil

7.CH-Soil

8. Druker-prager

9. cam-clay

I have a rock specimen and a soil specimen. During my mechanical measurements I observed that the rock reacts much faster on stress rate changes (observable by a sharp kink in the deformation curve) than a soil (no such kink). What is the explanation? Where can I find a publication dealing with this phenomenon?

What is the uniaxial compressive strength of westerly granite?

References would be appreciated.

dilemmas in rock mechanics..

Dear RG users,

I am wondering if there are good research topics related with industries need on “Wastewater threatment facilities” and “Solid waste landfills” considering only Geotechnical aspects.

I am looking forward for your messages.

Best Regards

Bekir S.F.

The most important current and future research to tackle problems related to industrial application in the field in soil and rock mechanics?

I am trying to model the strain-softening behavior of rock mass using UMAT subroutine. And, I am applying the 'static Riks method'. My model is running fine in abaqus under small loading. However, when comparatively large loading is applied the analysis is being aborted after 18% load application with an error msg, 'THE SOLUTION APPEARS TO BE DIVERGING. CONVERGENCE IS JUDGED UNLIKELY'.

I have checked the .msg file, .log file and the UMAT subroutine file, but could not find any thing helpful.

Kindly give me some suggestions for solving this problem.

Regards, Dipaloke

I am currently working on the effects of rock boulders upon a structure and I would like to simulate the dynamic impact force using Plaxis 2D. Since the duration of the impact is between 0-0,2 sec , how could I calibrate precisely a table of Impact Dynamic Force avoiding excessive Globar Error, and Log Info ''Accuracy condition not reached in last step''? Briefly, I'd like to mention that I tried to perform the analysis defining as accurately as possible a figure of Force domain.

Thank you in advance,

Paschalis M.

We are trying to decipher origin of magnetite-apatite ores from Evate deposit, Mozambique. I would like to know if someone observed textures like that illustrated in the attached figure, showing oval baddeleyite crystal decorated by euhedral spinels, all enclosed in magnetite with geikielite exsolution lamellae. Note that smaller euhedral spinels are regularly distributed in the magnetite, except for spinel free-zone around the baddeleyite grain. In our opinion, this may indicate the spinel growth controlled by the Ostwald ripening, i.e. dissolution of small crystals and their redeposition on the surfaces of larger crystals and nucleation centers. This interpretation is supported by the intersection of some spinel grains by geikielite exsolution lamellae, thus suggesting the spinel growth taking place in Fe-oxide melt. I would be grateful for some alternative interpretations (solid state diffusion?), including references to published works describing similar phenomenon.

In order to classify a rock mass foundation of a gravity dam to obtain its strength and deformability parameters using the Geological Strength Index (GSI), is the Ground Penetrating Radar (GPR) an adequate geophysical method to do it?

Hello everyone,

I am particularly interested in fissures in the soil mass and not on the surface such as shrinkage or tension cracks. Also, you can see an example photograph attached.

Thank you for your interest.

Regards,

Bekir SF

The current attention in improving the efficiency of mining energy minerals from the earth has encouraged concern in advances, difficulties and likely forthcoming development directions in numerical modeling for rock mechanics and rock engineering. Such modeling is necessary for studying the essential methods occurring in rock, for considering the anticipated and actual performance of structures built on and in rock masses, and hence for supporting rock engineering design. 

Would be reliable computing a finite element analysis of a dam-foundation system, using the rock mass parameters obtained through the GSI system, in order to evaluate the displacements in the rock mass, if you are using a software that not allow include information about the characteristics of discontinuities, only the rock mass stiffness?

Hey, I'm looking for a FEM analysis software to evaluate the displacements in a rock mass due to a presence of a specific gravity dam. I already have the strength and deformation properties of the rock mass and the dam.

Hello to all RG users,

I am currently searching for softwares to anaylze the behavior of discontinuous media such as rock masses. It would be a lot better if they are especially developed for Geotechnical Engineering applications. I am also aware that discrete element solutions such as UDEC and 3DEC would do the work. Are there any other softwares for the particular field? I am interested in Discrete Element Method (DEM) and Discontinuous Deformation Analysis (DDA) but I am also open to any other methodologies and softwares. Please keep in mind that they should be used on Geotechniques.

Thank you

Regards

Bekir SF

I want papers about ACV is indicating method for aggregate strength

Hello RG users,

The rocks are recrystallized limestones and dolomites and physically in various conditions such as in some areas the outcrop is fresh and intact, in some areas it is lightly or highly decomposed and weathered, even somewhere there are residual soils. Also, some areas contain discontinuities and some not.

Assume that I have the plain 3D geometry. I simply cannot assume that the whole area is homogeneous and has same characteristics.

My question is How can I efficiently represent such varying conditions (heterogeneity) in a 3D model based on FEM, DEM, FDEM etc. ? Is there any software capable of doing it?

Thank you!

Best Regards,

Bekir SF

Hello RG users,

I was wondering how can I determine the exact location of expected wedge, planar or toppling falures in rock slopes. Assume that I have already done kinematical analyses and results indicate such possible failure mechanisms. In this case, How can I possible know the location of the wedges etc. to prevent such an instability?

Thank you

Best Regards

Bekir SF

I am looking for some references or general comments that I can use for granular material, incorporating geologic conditions (i.e alluvium material, colluvium,or igneous, metamorphic and sedimentary lithology).

Additionally, I would like to ask for you opinion in earthdam construction what measures I need to take to avoid an excessive particle breakage under compaction and hydraulic load.

Regards

Johnatan

Dear All,

I would like to learn if the cut and cover tunnels have special joints between their segments such as immersed tunnels. For example, immersed tunnels have special gasket joints (gina, horn ,stirn, etc.), omega seals and shear keys. Is there any kind of joints for cut and cover tunnels? And anyone has longitudinal sketch of these tunnels showing connection details?

Thank you very much in advance.

Best regards,

Based on earthquake data, how we can define the type of rocks and minerals within the earth?

Hello,

I would appreciate it, if someone explain to me how I could estimate parameters of stoneley waves (such as arrival time, corresponding to the stoneley waves frequency or range of frequencies, velocity and so on...) that propagate in rock sample - limestone.

I've used ultrasonic pulser/receiver and oscilloscope for measurements and got this results ( please find attached ), but not sure what should be the next steps.

How I could differentiate where are P-wave, S-wave or Stoneley-wave moment of arrival and if there are any at all?

Never deal with this topic before, therefore would be grateful for guidance or advice on literature that I should read first.

Thank you.

I am working on roughness influence on shear strength of rock. I am facing problems regarding roughness of the upper block as I asked in the question. I am looking forward to the answer. 

Dear fellow researchers

In rock mechanics there are several methods to up-scale lab results to the field results (especially for Young's modulus) as it most of the times make a significant difference in analysis of tunnels, caverns, etc. However, in petroleum geomechanics the structure in question is a wellbore with a very small diameter (mostly less than 10 in.). I was wondering how much scale effect may be inflict in such a problem? Since the opening is almost as the size of the plugged core samples, is there any significant difference between lab mechanical properties and in-situ properties?

Problem with 10 node tetrahedral on RS3.

Results from using 4 node tetrahedral are similar to 6 node triangle on RS2 (and to analitical calculations) , but results with 10 node tetrahedral are very different, and not logical. Time calculation for 3d model of tunnel with 4 node tetrahedral is 20 minutes, and for 10 node tetrahedral is 16 hours.

What could be the problem with my model?

Sawai et al., 2012 summarized in the appendix the different approaches in these cases like the intercept method. What do you think is the best way to approach this experimental problem?