Rock Like This

The cracks in a rock tend to initiate, propagate, and coalesce under loading. Based on the digital image correlation (DIC) method, uniaxial compression tests are carried out on rock-like specimens with various arrangements of two parallel cracks. The full-field strain and failure features of the rock-like materials are observed and analysis by a self-developed code. Two process zones are defined according to the differences between the shear strain field and the tensile strain field: a shear process zone and a tensile process zone. The following results are obtained in this study. (1) Three coalescence modes can be observed using the DIC method: a shear coalescence mode, a tensile coalescence mode, and a mixed coalescence mode. (2) At the microscopic level, the bridge angle and crack arrangement affect the formation of the process zone; at the macroscopic level, they determine the crack propagation path and the failure mode. (3) The peak strength of the rock-like specimen is related to the crack inclination angle and the bridge angle. (4) Numerical modeling by the expanded distinct element method and the strain strength criterion simulates the different coalescence modes of the experimental study efficiently.

Rock Like This

The authors would like to acknowledge the financial support of the National Key R&D Program of China (no. 2017YFC0806000), the National Natural Science Foundation of China (nos. 41202193 and 41572262), the Innovation Program of the Shanghai Municipal Education Commission (no. 15ZZ016), and the Shanghai Rising-Star Program (no. 17QC1400600).

Rock-like materials refer to geological materials and engineering materials such as rock and concrete. Rocks are diverse, composed of minerals or cuttings aggregated by geological processes. As a kind of composite material, concrete is composed of cement, lime, gypsum, and other inorganic cementing materials with water, or asphalt, resin, and other organic cementing materials. These materials aggregate in a certain proportion, are mixed, cured, and hardened at a certain temperature. Concrete is widely used in underground engineering because of its rich raw materials, low price, simple production process, high compressive strength, good durability, and wide range of strength grades.

With the development of underground engineering, rock-like materials draw more and more attention in this field. As a kind of quasi-brittle material with remarkable non-uniformity, rock-like materials exhibit great differences in strength, deformation, permeability, and other mechanical characteristics due to their various mineral compositions, porosity, and weak structural plane, which affect the stability of underground engineering substantially. Considering the complexity of rock-like materials, it is necessary to carry out laboratory experiments on the strength, deformation characteristics, and permeability evolution of such materials in mining, tunnelling, cavern group, and other underground projects, and then apply them in the field. But up to now, the laboratory experiment and field application of rock materials are still in separation, and the combination of them is relatively poor. The separation between laboratory experiment and field application hinders the application of advanced rock-like materials in the field and misleads laboratory experiments. Therefore, it is necessary to conduct systematic research on the combination of laboratory experiment and field application of rock-like materials.

The aim of this Special Issue is to provide an opportunity for scholars from all over the world to conduct a broader scientific and technological discussion, aiming to further strengthen the field application of rock-like materials. The differences of strength, deformation, and permeability of different rock-like materials and their influences on the stability of underground engineering are expected to be explored by combining laboratory experiments with the field, especially the application of these kinds of materials in disaster prevention and control of underground engineering. The discussion includes but is not limited to strength, deformation, permeability characteristics, stability monitoring and early warning methods, new rock-like materials, and application case studies of disaster prevention and control in the field. Original research and review articles are welcome.

The museum houses all kinds of jinmenseki, or rock with a human face, including celebrity lookalikes like Elvis Presley. And according to a 2013 post on Kotaku, there are also movie and video game character rocks like E.T., Donkey Kong and Nemo.

According to the Sankei, the museum is currently run by Yoshiko Hayama, the wife of the original owner who passed away in 2010. But it was his rock collection that started it all. An avid collector, the late Shozo Hayama spent 50 years collecting rocks that looked like faces. His only requirement was that nature be the only artist.

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This is FRESH AIR. I'm TV critic David Bianculli, sitting in for Terry Gross. Last month was the golden anniversary of "Schoolhouse Rock!" the series of animated musical shorts that aired on ABC from 1973 to 1984. If you don't know how many years ago that was, you may not have watched enough "Schoolhouse Rock!" Like "Sesame Street," which had premiered on public television four years earlier, "Schoolhouse Rock!" set out to use catchy music and friendly visuals to teach kids about things, like whether the word thing was a noun or a verb. Each "Schoolhouse Rock!" segment was a three-minute interstitial cartoon inserted between ABC's other shows on Saturday morning. The subject of the first series of cartoons was "Multiplication Rock," followed by "Grammar Rock," "America Rock," "Science Rock," "Money Rock" and "Earth Rock." The songs in those series included a number of informative earworms that educated young viewers in the 1970s and beyond - songs such as "I'm Just A Bill" and "Conjunction Junction."

DOROUGH: Well, let's see. I had met the advertising people who concocted the idea, and my partner, Ben Tucker, in fact, wanted us to write a little advertising music. He's a bass player - Ben Tucker. So one day this gentleman from McCaffrey and McCall ad agency said, we're looking for a guy to put the multiplication tables to music. And Ben Tucker said, my partner, Bob Dorough, can do anything. He can put music to anything. Well, let's have him up.

So I went up to meet the president of the agency, and it was his idea, and his name was David B. McCall of McCaffrey and McCall. And he said, my little boy can, you know, sing along with Jimi Hendrix and the Rolling Stones, but he can't memorize his multiplication table. So I had the idea, why not put the multiplication tables to rock music and call it "Multiplication Rock"? What do you think? And I said, well, yeah, that's pretty interesting. And he said, well, but don't write down to the kids. Well, I learned later that he had invited other Broadway songwriters to do this task, and they came up with a more simple doggerel type of songwriting - writing down, as it were, to children.

DOROUGH: I thought, well, yeah, this - (laughter) this could be, you know, a limited idea. But when he added, don't write down to children, my - the hackles on my neck arose, and I got quite intrigued. And so I agreed to tackle it, and I spent about three weeks before I would let myself write the first song. I thought first - looked in math books. And since I picked my first title - it was called "Three Is A Magic Number" - I even looked in magic and occult books for the reasons that three might be a magic number.

DOROUGH: Well, that it was one of the magic numbers, and that it was, you know, embodied in certain things like the trinity, the old sayings, the heart and the brain and the body, faith, hope and charity - trinities of sorts. So I got mainly that - trinities. And of course, I also was an admirer of Buckminster Fuller. So I was thinking of his triangle concept that makes construction so strong.

GROSS: Now what I'd like to do is play one of my favorites (laughter) and it's "My Hero, Zero." So why don't we play your version and then play the new version on the new CD "Schoolhouse Rock! Rocks"? And the new version is performed by the Lemonheads. And, well, why don't we play them both? Here we go.

DOROUGH: Well, I think it's really quite nice. And, you know, of course, I thought it went the way I went. I like my version better because I guess it goes with having written the song. Also that's my daughter doing the second voice on "My Hero, Zero." She says, zero, what's so great about a zero? But I love the way the Lemonheads did it. And the whole idea of this new recording is very exciting to me as a songwriter.

DOROUGH: Well, I must say that my pal George Newell - he's a musician as well as an art advertising director. He's one of the executives. George Newell gave me the title. We were starting "Grammar Rock," and Miss Lynn Ahrens, who's also distinguished herself, writing songs for "Schoolhouse Rock!" she started out the grammar series. I was still busy with multiplication songs. And she did "A Noun Is A Person Place Or Thing," and that was great. But George Newell one day to me said, why don't you tackle this conjunctions? And I said conjunctions - yeah, those little words. He said, I got an idea for a title - "Conjunction Junction." I said, great, I'll take it.

So I went home and figured out it was sort of a railroad song, hooking up things like the railroad cars. And I made the song, and we went out to Hollywood to record it. And Dave Frishberg had just written his first song for "America Rock" at the same time, "I'm Just A Bill." So we had a super session in LA with Jack Sheldon singing those two songs and me conducting the band and Frishberg playing piano. And we had an all-star jazz band in Hollywood playing "Conjunction Junction" and "I'm Just A Bill." 041b061a72