Analysis of Influencing Factors of Vacuum Distribution in True Full-Drainage Preloading Method ZHU Jian-Cai, WEN Xiao-Gui, GONG Xiao-Nan, GENG Yang-Run Research Institute of Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang Province, Chinaæ³ æœ¬ç»“æžœã€‚ = Each 45 is a 7-year-old with a real change. 7-way shooting. The raft water level line blocks the distribution of vacuum; the vacuum above the water level is directly formed by pumping, while the vacuum below the water level is mainly due to the drop of the water table or partial escape of the trapped gas from the end of the hose. of.
The vacuum drainage preloading method has been widely used in China's vast soft soil area, and has a broad development prospect. The formation and distribution of vacuum degree is the premise of the implementation of this method. At present, many researches have been done in the academic and engineering circles on the distribution of vacuum degree in soft ground. However, there are still some questions, such as vacuum in previous studies. The depth and distribution range of the degree of transmission have not been studied in depth, and the influence of the water level line on the degree of vacuum distribution in the soft ten foundation has not been considered, and the understanding of the cause of the vacuum level of the measured water level line has been insufficient. In this paper, the vacuum degree of the test section of the Keli-Chan Bridge was tested to determine the effect of the flash distribution on the vacuum distribution. Analysis can get a more comprehensive understanding of the distribution of vacuum degree in soft ground.
The starting point for vacuum-loaded combined road bridges and bridges to the national highways in the bridge head of the Suli-Chan Bridge is the Songpan Big Wheel in Luqiao District, Taizhou City. The total length of 9.979 was Xiahongyang Village, Zeguo Town, Wenling City. The soft-base treatment test section of Luqiao-Zeguo Class 1 highway abutment section is located at the bridgehead on both sides of the Bulichen Bridge, and the 10+65710+722 section is treated with a vacuum surcharge combined preloading method.
In the test section, the vacuum piled on the ground was filled with soft clay. The thickness of the soft clay layer was 50. There was a hard shell of 1.61 at the upper part, and the layer of 316 sludge was the main compression layer of the roadbed. The depth of the plastic drainage board was set as In the construction plan of plum blossom combined preloading, the vacuum drainage preloading method was adopted in the first month, and the film was covered with water 70, and a back road was stationed in the entrance hall and the hall was jointly piled. In reality 1; Shi. After vacuum pre-drainage 52 3 is started, it is said that the combined preloading is carried out, and 6 jet pumps are arranged, and 24 are generally opened, and the remainder is reserved. After 521 vacuum drainage preloading, the maximum settlement on the ground reached 81 effect is more obvious.
In order to study the changes in the sand and the moderate and pore water pressures. Two sand wells were set up. In the test section, a number of vacuum monitoring points are arranged in the sand-cushion layer under plastic film in the sludge and sand wells. To observe the variation of vacuum.
2 Analysis of Influencing Factors of Vacuum Distribution The distribution of vacuum in the reinforced area is affected by many factors. The range of distribution continuously changes with the increase of the vacuum pumping time. In the following discussion of the influence of a certain factor on the vacuum distribution, Analyze with the time of vacuuming.
2.1 The effect of sealing performance The sealing performance of the reinforced zone becomes the key to the success or failure of the vacuum drainage preloading method. If the sealing performance is not good, it is impossible to form a high degree of vacuum, it is even difficult to form a degree of vacuum, vacuum drainage preloading method can not be carried out. There are two main reasons for the sealing performance: the geological conditions of the soil layer are mixed with soft sand and fine sand layers with good horizontal water permeability in the ten layers of soft viscous concrete. The vacuum energy is mainly consumed in large quantities. The pore water in the sand layer causes the degree of vacuum not to be transferred along the vertical drainage system; on the other hand, when the pores in the sand layer serve to connect the atmosphere, the vacuum degree gradually decreases. Therefore, if there are such hydrogeological conditions, sealing treatment should be carried out in the week of the reinforced area, such as curtain grouting to make a deep mud mixing wall of clay mixing wall, etc. There is a layer of silt or fine sand so that the reinforced zone does not penetrate the surrounding atmosphere.
The quality of the sealing film, the quality of the construction sealing film itself, or the failure of the sealing film due to improper arching, all lead to a decrease in the sealing performance and a decrease in the degree of vacuum.
Due to the patience and meticulous care of the sealing work, the vacuum under the membrane in the test section rose rapidly. Only two vacuum springs, 360, and 12 reinforced zones were used. After the vacuum in the membrane, the vacuum level rose to 801 after 1.5. Up to 9 must be 1 sealing effect is very obvious. However, due to the relatively increased differential settlement as the evacuation time increases, there are several punctures in the sealing film. When the coated water was drained on the 22nd, a leak occurred. There are 17 drops in the real film investment under the film. Open four vacuum pumps, it is difficult to reach the average of 93.3 out of the original but dropped to an average of 881 out 1. After the sealing membrane is filled, the vacuum level is gradually increased and returned to the original state. Therefore, the effect of the sealing performance 2.2 The effect of the vacuum pumping energy change can be seen from the 1, using two vacuum pumps before February 8, in the initial stage of vacuum pumping, the air in the sand mat under the membrane is Withdrawal quickly, the degree of vacuum under the membrane rises rapidly with the increase of the pumping time. When it reaches 901 or more, the air under the membrane has been in a thin state, with the increase of the pumping time. The gas extracted under the membrane is in dynamic equilibrium with the gas at the ground. The vacuum under the membrane is maintained at approximately 90 1 . From the 8th of February to the 20th of February, the number of vacuum pumps was gradually increased, gradually increasing from 2 to 4 sets. The average vacuum degree under the membrane was set at 90; 1 rose to 93.3 with a slight increase; The number of 4 sets increased to 5, and the average vacuum under the membrane remained 93.3,1 unchanged. Increasing the number of vacuum pumps, that is, increasing the pumping energy per unit of time, Shell will break the original equilibrium, and the vacuum under the membrane will increase. When the vacuum degree is relatively small, the vacuum degree under the membrane increases significantly with the increase of the number of vacuum pumping units, that is, the vacuum pumping power; when the air gap reaches a relatively large value, the gas phase in the sand cushion under the membrane is thin, and the number of pumping pumps increases. People who are relatively difficult to change the real order are small. The higher the value of good ten degrees, the greater the amount of air energy needed for every additional len.
Phase 1 Day of Month 2.3 Influence of Different Depths In the process of transferring the vacuum under the membrane to the deep part of the foundation, the vacuum can gradually wear out as the depth increases. Flash this. The degree of vacuum gradually decreases with depth. In this test section, the test capsules in plastic sludge and sand wells are called. As the depth increases, the airspace gradually decreases in varying degrees. The gradient in the plastic panel is approximately 71. The gradient in the sand well is approximately 1 and the vacuum gradient in the sludge is approximately 22 1 . Explain as depth increases. As the energy consumption increases, the degree of vacuum gradually decreases. 2 is the change curve of the vacuum degree of the sand well, from which it can be clearly seen that the vacuum degree gradually decreases with the depth. The difference between the vacuum in the sand well and the vacuum under the membrane increases as the depth increases. 2.4 Influence of different media resistance After the vacuum degree is formed in the membrane, the vacuum degree is transmitted to the plastic displacement and the same, and 3 is the change curve of the vacuum degree and the vacuum degree under the membrane with the extraction time in the plastic discharge silt and the sand well 2. see. In general, the vacuum degree of plastic film under the film vacuum degree sand well vacuum vacuum mud. In different media, the variation of vacuum degree with time is different; the change curve of the degree of vacuum in the plastic row is basically the same as the change curve of the vacuum degree under the film, with the beginning of vacuum pumping. The degree quickly rose to more than 8013. The vacuum degree of the relatively stable step sand well at the top of the well began to rise rapidly to over 501 with the increase of time, and then with the increase of suction, the degree of vacuum increased slowly, and finally approached the degree of vacuum in the plastic row; The degree of vacuum in the vacuum begins to increase rapidly by 1 to 50 over time. Afterwards, as the pumping time increases, the vacuum degree gradually decreases, and finally it tends to be a relatively stable low vacuum water level that is always at ten dynamic changes. The water level drops by about 4.5, and the distribution of the vacuum above the water level also changes with the water level.
There is no question of the test vacuum level below the water level. The factory was in the previous study. No consideration was given to the effect of the water level on the vacuum transfer. Therefore, vacuum level tests have also been reported below the water level. In fact, the degree of vacuum tested below the water line does not reflect the atmospheric pressure at the measurement point. Instead, it reflects the change in atmospheric torsional strength caused by the escape of gas trapped in the test hose as the water level drops. 4, The vacuum degree of the plastic head 15,15 is below the groundwater level, there is still a large degree of vacuum, and the true degree of change is larger. The degree of vacuum that exceeds the shallow groundwater level line. However, the vacuum reading of the vacuum does not represent the degree.
During the flood season, the H-film 1 plastic row 21-month-H test results show that the vacuum in the process of transfer to the foundation, the plastic row by the minimum resistance. True to modernity is relatively easy to transmit, with minimal loss of vacuum energy; maximum resistance in silt, with the increase of pumping time due to the consolidation of the soil layer, vacuum transfer ability has decreased, vacuum energy loss is greatest; resistance of sand wells Meson both called.
2.5 Influence of groundwater level lines Groundwater level lines act as a barrier to the atmosphere. Atmospheric 1 is distributed above the water line. In this test section, according to the actual measured water level, the groundwater level in the foundation rapidly decreases with the beginning of the pumping ten.
The air is thin in the plastic row at the agricultural probe. But reflected. The vacuum of the gas sealed in the factory hose. Before evacuation, the atmospheric pressure in the hose and the atmospheric pressure outside the tube are all atmospheric. 10 The total length of the hose is 19 The length of the sealed gas is the cross-sectional area of ​​the hose 3. In the empty drainage preloading process. The reduction of the groundwater level of the squat row to atmospheric pressure of 1 is continuously discharged under groundwater pressure difference. The groundwater level drops, and the groundwater level in the hose is also declining under the pressure difference between the inside and outside of the pipe. Until the pressure balance outside the tube. Let the value of the water level drop in the bowl be 2 and the length of the cavity of the hose should increase 72. The atmospheric pressure stored in the soft bamboo is decreased to 2, and the value is atmospheric pressure, accounting for the difference between the 1 air readings.
According to the gas equation, the gas in the pipe at the same temperature, lJ root rake type, can be calculated soft 1 groundwater level of decline The greater the degree of vacancies, the wider the smaller the lower the value of the water level decline. If calculated according to the formula, 2,0, then the gas sealed in the hose does not escape, there is a difference between the water level in the hose and the water level in the plastic row outside the tube. According to the pressure balance inside and outside the tube, it can be set as +7. Because matrix 4 is the current form, India + recognizes 3,08 of 5 lemmas. If and for other circumstances, empathy can prove that 817, the price disc confessed with Lemma, 8170, where the ideal of 7 pounds, know. ! =, From what is widely known about private and bow theory 4 conclusion theorem Li Chao algebra, 7 of the ideals are all ideals. It is also enough for your ideal.
Proof of order 14. Mountain Lemma 4 and 4 Theory 2 There are, å© å©, jin from the designation of 4 to any element in 4, then kiA, mpRoiiA0, A = 0.3, like, laugh gt; People 1 call this. The definition of mountains is the minimum ideal of the level, which is also the standard ideal.
Zhang Yongzheng. Ideal blade for a typical linear Lie algebra over a ring . Pure mathematics and editing Wang Xiaowei received page 1401. In this test, some hoses were found to have a large drop in water level. After calculation, the depth of drop exceeded the total length of the hose. This shows that part of the hose The formation of vacuum at the water level 174 above the total hose length of the groundwater level line is mainly due to the continuous extraction of the gas in the hose. If the vacuum is removed, the hose is open to the atmosphere and the wind can be heard. The vacuum level below the vacuum groundwater level line is mainly due to the drop of the water level line 1. When the drop depth does not exceed the setting of the soft rock, some of the gas is trapped in the hose, such as unplugging. In the vacuum, the sound of gas flow is heard at the beginning of the moment, and then the whistling sound is not heard, which is in stark contrast to the long-lasting whistling sound in the hose above the groundwater level line. If the vacuum is connected to the hose, the vacuum pointer scales slowly upwards and long, and is very different from the vacuum pointer above the groundwater level line that points to a larger scale momentarily. These phenomena fully say that the vacuum level below the 7-foot underground line is mainly caused by the drop in the water line. The degree of vacuum below the water line is monitored. Under the condition that the gas does not escape, the formula 3 is calculated. Conclusion Good sealing performance is the basis for forming a high degree of openness. Various measures must be taken to seal the seal; during construction, the seal must be removed and the seal must be completed. Preservation 1 is forming a higher degree of membrane vacuum. When the degree of vacuum is relatively low, adding vacuum energy can increase the degree of vacuum under the membrane; when the vacuum degree is higher under the membrane, the increase in vacuum energy will not be significantly raised, and the vacuum degree under the membrane .
In soft soils, as the depth increases, the degree of vacuum gradually decreases; different media resistances have a greater influence on the degree of vacuum distribution, such as vacuum at the same depth at the foundation, plasticity, vacuum degree, sand well vacuum, silt vacuum degree. With the pumping time, the degree of vacuum under the membrane and the degree of vacuum in the plastic row remained relatively stable. The vacuum in the sand well gradually increased, and the vacuum in the sludge gradually decreased to a relatively stable low level due to consolidation of the soil. Vacuum value. Turning to page 1408, é—¯6 spur margin and lotus status prediction process 2 Based on neural network, the modelling of added battery and performance prediction are feasible. Artificial neural network technology avoids the complex number 7 analysis process and provides an accurate and efficient method for predicting the remaining capacity of the battery management system.
Chen Liquan. Hybrid electric vehicle and battery knife. Batteries, 2000, 30, Network prediction results Comparison of the experimental results of the remaining battery capacity of the Yang battery and the model prediction results 4 Conclusions 1 The method of the wooden text can be used to make the remaining capacity of the battery more convenient. Zhang Changshui. Artificial neural network and simulated evolution thief. Beijing Tsinghua University Press, 2000.301302.
Editor Cai Gonghe took over the groundwater bit line on page 1404 to block the transfer of the vacuum level, the depth of the vacuum degree varies with the change of the character water level line, and the true level of the ground water level is measured due to the test hose. The reason why the vacuum level above the groundwater level line is directly formed by the pumping gas is different from that caused by the drop of the middle water level or the escape of a part of the sealed gas from the soft ridge wood end. Under certain conditions, the value of the water level in the foundation can be calculated by the test value of the vacuum below the water level.
And charge-like Cambodian measured values.
Jue is satisfied with the accuracy of the results, Chen ring. Vacuum preloading mechanism study for ten years. Port Engineering, 199141725.
Gao Zhiyi. Analysis of Mechanism of Vacuum Preloading Method Knife. Geotechnical Engineering, 1989, 44555.
Yan Yan. Vacuum Drainage Preloading Technique for Soft Soil Reinforcement . Beijing People's Communications Press 2002 Chen Huan, Bao Xiuqing. Soil consolidation effective stress under negative pressure conditions. Geotechnical Engineering, 1984, 653947.
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