CN-116840078-B - Evaluation method for rock energy release effect

Abstract

The invention discloses an evaluation method of rock energy release effect, which comprises the steps of taking a plurality of rock samples in a region to be tested, taking one of the samples to obtain the internal fracture degree, obtaining fracture development characteristic value P1 before a drop test, setting a counterweight and a contact speed, carrying out the drop test, observing by a high-speed camera, obtaining fracture development characteristic value P2 of the sample after the drop test, obtaining fracture development characteristic value change delta P according to the P2 and the P1, replacing the samples, repeating the steps, adjusting the counterweight and the contact speed each time of the drop test, fitting to obtain the relation among the release amount, the release speed and delta P, carrying out a uniaxial compression test on the complete rock sample to calculate the energy release amount and the release speed, obtaining fracture development characteristic value change delta P according to the energy release amount and the release speed, and combining a curved surface graph, and evaluating the energy release effect. The invention fully considers the energy release speed, thereby being capable of more accurately reflecting the impact tendency of surrounding rock.

Inventors

• LUO SHENG
• WANG JILIANG
• FU PING
• HAN XIAOYU
• ZHOU CHUNHUA
• AI KAI
• ZHANG XINHUI
• WANG BIN
• ZHOU CHAO
• Bi Fajiang
• HE MENG
• DONG ZHIHONG
• DING XIULI
• Ren Hengqin
• XIANG JIABO
• LIU YUANKUN
• DENG ZHENGRONG

Assignees

• 云南省滇中引水工程有限公司
• 长江水利委员会长江科学院

Dates

Publication Date

20260508

Application Date

20230605

Claims (4)

1. 1. The method for evaluating the rock energy release effect is characterized by comprising the following steps of: Step 1, taking a plurality of rock samples in a region to be measured; Step 2, taking one of the samples to obtain the internal fracture degree, and taking the average value of the fracture degrees at a plurality of section positions of the sample as a fracture development characteristic value P1 of the sample; step 3, setting a counterweight m and a contact speed v for a drop test, observing the drop test by using a high-speed camera, and calculating and obtaining the release delta E and the release speed Ev of the sample according to the counterweight m, the contact speed v and the observation data of the high-speed camera; Step 4, acquiring the internal fracture degree of the sample again, acquiring a fracture development characteristic value P2 of the sample after the drop hammer test according to the method of the step 2, and acquiring a fracture development characteristic value change delta P according to the fracture development characteristic value P2 and the fracture development characteristic value P1 in the step 2; Step 5, obtaining the relation between the release amount delta E and the release speed Ev of the sample and the change amount delta P of the crack development characteristic value according to the steps 3 and 4; Step 6, replacing the sample and repeating the step 2-5, and adjusting the counterweight and the contact speed of the sample during each drop test to obtain a series of relation points between the release quantity delta E, the release speed Ev and the crack development characteristic value change quantity delta P, and fitting the relation points to obtain the relation among the three; Step 7, performing a uniaxial compression test on the complete rock sample to obtain a full stress strain curve, calculating energy release amount and release speed by combining the loading speed, obtaining a crack development characteristic value change amount delta P according to the energy release amount and release speed and the correlation of the step 6, and evaluating an energy release effect according to the crack development characteristic value change amount delta P; In the step 3, a high-speed camera is adopted to observe and obtain a time difference delta t from the falling weight to the sample with the downward movement speed of 0 and a maximum height h of reverse movement after the falling weight speed is 0; in the step 3, the energy release amount deltae is obtained by the contact speed v, the drop weight m and the reverse movement height h, and specifically comprises the following steps: ΔE=mv 2 -mgh; The release rate Ev is obtained from the time difference Δt and the release amount Δe, specifically: Ev=ΔE/Δt。
2. 2. The method of evaluating the effect of energy release from rock according to claim 1, wherein the initial properties of the plurality of rock samples taken in the region to be measured in step1 are close.
3. 3. The method of evaluating the effect of energy release from rock according to claim 1, wherein in step 6, the weight adjustment range is such that the sample is substantially not destroyed to the sample is completely destroyed.
4. 4. The method for evaluating the energy release effect of rock according to claim 1, wherein a rock-soil CT visual test is used to obtain the internal fissure degree of the sample.

Description

Evaluation method for rock energy release effect Technical Field The invention belongs to the technical field of hydraulic and hydroelectric engineering, and particularly relates to an evaluation method of rock energy release effect. Background The rock burst is a dynamic instability phenomenon caused by excavation unloading under the high ground stress condition. The stress state of the rock on the wall of the cave is changed into two dimensions or one dimension by the excavation disturbance, so that a free surface is provided for the cast damage of the rock, and the crack expansion and the strength weakening in the rock are caused. Rock burst is one of the worldwide problems in underground engineering, and has attracted more and more attention from the domestic engineering geology and tunnel engineering world. The method has the advantages that the result is light, the construction progress is influenced, the equipment safety is endangered, the personnel safety is even endangered, the rock burst phenomenon is deeply researched, targeted information can be provided for relevant tunnel disaster prevention and control, and the method has important guiding significance for safety construction and design in railway, mining and hydropower construction in China. From an energy perspective, a rock burst is the result of release of elastic strain energy stored inside the rock mass, and externally appears as a failure of the surrounding rock. In the process of deep rock mass excavation, the phenomenon of strain energy release of brittle hard rock is very widely occurred. In the existing hydropower engineering construction of China, most of rock burst induced by deep rock mass excavation is strain rock burst, and the main expression form of the rock burst is local deformation or small-amplitude rock mass projection. Most of reasons for the generation of such rock burst are that the stress state of surrounding rock caused by blasting excavation is changed to cause the reduction of the energy storage limit of the rock mass and the accumulation and dissipation of surrounding rock energy, when the energy in the rock mass exceeds the energy storage limit of the rock mass, the rock mass is damaged, further the strain energy stored in the rock mass is released, and the nearby rock mass is damaged due to the energy released by the rock mass damage. Meanwhile, the damage and energy release of the rock mass can excite stress waves, and the energy carried by the stress waves can become an energy source for breaking the balance state of the rock mass in the limit balance state at a longer distance, so that the rock mass is unstable and damaged. At present, the research on the release rule of energy in the rock explosion process is insufficient, but the basic characteristics of the rock explosion are still that the release of energy is the basic characteristics of the rock explosion, and the more the energy released by the rock mass is, the greater the tendency of the rock explosion is. Because of the complexity of the energy release process, the existing energy release indexes also often only consider the energy release amount, and fail to consider other indexes of energy release, but in engineering practice, there is irrational, so that it is necessary to develop and consider other indexes of energy release, such as release speed, so as to supplement and perfect the existing indexes only considering the energy release amount. Disclosure of Invention The invention aims to provide an evaluation method for rock energy release effect, aiming at the defects of the prior art, and the method fully considers the energy release speed and the like, so that the impact tendency of surrounding rock can be reflected more accurately. In order to solve the technical problems, the invention adopts the following technical scheme: A rock energy release effect evaluation method comprises the following steps: Step 1, taking a plurality of rock samples in a region to be measured; Step 2, taking one of the samples to obtain the internal fracture degree, and taking the average value of the fracture degrees at a plurality of section positions of the sample as a fracture development characteristic value P1 of the sample; step 3, setting a counterweight m and a contact speed v for a drop test, observing the drop test by using a high-speed camera, and calculating and obtaining the release delta E and the release speed Ev of the sample according to the counterweight m, the contact speed v and the observation data of the high-speed camera; Step 4, acquiring the internal fracture degree of the sample again, and acquiring a fracture development characteristic value P2 of the sample after the drop hammer test according to the method of the step 2, wherein the fracture development characteristic value P2 and the fracture development characteristic value P1 in the step 2 obtain a fracture development characteristic value change delta P; Step 5, obtaining the re