If there was no magic axe and no divine power, how long would it take Chenxiang to rescue his mother?

Image source: Qiantu.com

Splitting the mountain to save the mother, also known as opening the mountain to save the mother, is a mythological story about Chenxiang using his magic axe to split Huashan and rescue the Three Holy Mothers. If you have the opportunity to climb to the Cuiyun Palace on the top of the West Peak of Huashan, you will definitely see a large stone with a large crack next to it. It is said that this is where Chenxiang split the mountain to save his mother. Huashan mythology is rich in subject matter and the well-known "Splitting the mountain to save the mother" is a typical example of this type of mythological story.

Huashan is located in the Huashan area in eastern Shaanxi, bordering the Qinling Mountains in the south and overlooking the Huangwei River in the north. Since ancient times, it has been known as "the most dangerous mountain in the world". Huashan is a typical representative of my country's granite landforms, and its magnificence and steepness have fascinated countless people.

Chen Xiang split the mountain with the help of divine power. If he didn't have divine power, would it be possible for an ordinary person to complete this "super project"? To answer this question, let's first get to know granite.

01 What kind of rock is granite?

Granite is a kind of rock that is both common and special. It is common because it is an important part of the earth's continental crust and can be found everywhere; and it is special because it is an important symbol that distinguishes the earth from other planets in the solar system. Therefore, granite has a special meaning in geology. The origin of the name of granite is also very interesting. It is mainly composed of minerals such as quartz, feldspar, and mica. The "flower" in the name refers to the structure, that is, it looks like a flower; and the "hill" refers to its strong hardness, so it is called granite.

Granite is widely distributed in my country. Many famous mountains and rivers, and many classic landforms seem to be inseparable from granite, including Mount Hua in the west, Mount Heng in the south, Mount Tai in the east, as well as Mount Huang in Anhui, Mount Jiuhua in Chizhou, Anhui, Mount Laoshan in Qingdao, Shandong, and Mount Sanqing in Jiangxi.

Granite was not actually on the surface of the earth from the beginning. Granite is a magmatic rock, as the name suggests, a rock related to magma. It was formed continuously in the earth's crust due to the upwelling and condensation of magma in the long geological history, and later emerged on the surface step by step during the movement of plates.

Granite is widely used, especially as a building material. It is often seen in streets and alleys, squares and parks, and is used to build bridge piers, arches, dams, harbors, roads and other sculptures. It can also be used as acid-resistant linings and containers in chemical and metallurgical production. Not only that, it also has strong corrosion resistance and is widely used in the storage of chemical corrosive products. It is even made into stone pots due to its high temperature resistance and good heat preservation effect. These uses are all due to the physical and chemical properties of granite itself.

02 How long does it take Chenxiang to save his mother?

In geology, rock has a strict definition. Rock refers to a naturally occurring mineral aggregate with a stable shape. Therefore, many characteristics of rock are determined by the minerals that make it up. Take the hardness of rock, for example, as one of the rock physics indicators, it can be well explained. There are many types of rocks that have been discovered, and there are dozens of common ones. The hardness of different rocks varies greatly.

German mineralogist Frederich Mohs classified minerals of different hardness into 10 grades, with one mineral as the standard, from 1 to 10: talc, gypsum, calcite, fluorite, apatite, feldspar, quartz, topaz, corundum, diamond. Common rocks are used as examples, such as limestone, dolomite, claystone, basalt and granite. The main mineral components of limestone are calcite (CaCO3) and a small amount of dolomite (CaMg[CO3]2), and its Mohs hardness is 2~4; dolomite is mainly composed of dolomite and a small amount of calcite, and is harder than limestone, with a Mohs hardness of about 4~5; claystone is more complex, mainly clay minerals (content greater than 50%), mainly silicate or aluminosilicate minerals, such as kaolinite (Al4[Si4O10](OH）8), illite (K<1Al2[(Al,Si)Si3O10](OH)2·nH2O), etc., with a hardness of 1~4, which will increase with the increase of silicon content; basalt is mainly composed of minerals such as pyroxene, feldspar and olivine, with a hardness of 5-7; while granite is mainly composed of minerals such as feldspar, quartz, mica and amphibole, with a hardness of 6-8, and is a very hard rock. According to common sense, the harder the rock, the less likely it is to be damaged.

Huashan is 15 kilometers long from east to west and 10 kilometers wide from north to south, with a total area of ​​about 148 square kilometers. The South Peak is 2,154.9 meters above sea level, making it the highest peak in Huashan. The West Peak is where Chenxiang split the mountain to rescue the Three Holy Mothers. Because there is a huge rock in front of Cuiyun Palace on the top of the peak that looks like a lotus, it is also called Lotus Peak. Its altitude is 2,082.6 meters.

Since Chenxiang does not have a magic axe or divine power, he does not need to think of splitting the West Peak of Mount Hua, because there is no need to do so. Not splitting the mountain does not mean that he cannot save his mother. Chenxiang only needs to choose the appropriate tools and dig a cave or tunnel from the foot of the mountain to his mother's location to rescue her. Chenxiang can choose from many tools, including geological hammers, shovels, stone picks, electric drills, splitters, excavators, and shield machines. These different tools depend on Chenxiang's mother-saving funds.

As mentioned before, Huashan is 15 kilometers long from east to west and 10 kilometers wide from north to south. We assume that the location of Chenxiang Mother is at the center of the bottom of Huashan, and the narrowest part, which is 5 kilometers away from the foot of the mountain.

Image source: Qiantu.com

Next, we choose two extreme tools for simple calculations.

In the first case, Chen Xiang was penniless and could only buy a geological hammer, a masonry chisel and a shovel. Based on the author's many years of experience in stone-breaking, it is not easy to dig a 50-centimeter-diameter tunnel from the granite, which is just wide enough to accommodate an adult. It will become more and more difficult as the tunnel goes deeper. It is necessary to consider taking the rubble under the bridge out of the tunnel. Assuming that the average speed of digging is 1 meter per day, Chen Xiang needs to dig for 5,000 days (5,000/365≈14 years). With the help of his uncle Yang Jian, the two of them work in shifts day and night, and the construction period is shortened by half to 7 years.

In the second case, Chen Xiang does not need to consider the issue of funds and can hire any tools he wants. Take the American Bertha as an example. It represents the most advanced technology. The overall appearance is over 100 meters long, the diameter is over 17 meters, and the weight reaches 7,000 tons. The construction efficiency is also amazing, with a speed of 3.6 meters per hour, which is almost three times that of traditional tunnel boring machines. Let Bertha work 24 hours a day without interruption. According to this speed, a 5km tunnel can be completed in only 58 days. However, Bertha is too expensive, costing Chen Xiang 500 million yuan.

The above two situations are both ideal. The first situation does not take into account the time that Chen Xiang and Yang Jian need to rest due to fatigue. The second situation does not take into account machine failures or special situations, such as forced suspension of work due to sudden incidents such as fractures, rock bursts, and water leaks during tunnel excavation. Taking these factors into account, the time may be slightly increased, one year in the first situation and one month in the second situation.

It seems that Chenxiang can rescue his mother no matter what. Although 8 years is too long and 3 months is too expensive, there is always a way.

Author: Dong Hanwen

Source: WeChat official account of China Science and Technology Press