Piling machinery belongs to heavy industry products. At present, the world's most developed countries are mainly Germany, Italy and Japan. The cutting-edge equipment and construction methods are usually first developed by these countries, followed by the United States, The United Kingdom, France, the Netherlands, Finland and other countries. There are three largest pile machinery markets in the world: Bao'e, Tucheng, and Casa Land, which rank the top three in annual sales.
In the past two years, driven by the development of China's transportation industry, energy and construction industry, especially by the construction of high-speed railway, China's pile engineering machinery industry has ushered in a period of rapid development.
1、The development of piling engineering machinery in China
China's construction machinery industry has benefited from the sustainable development of the national economy, fixed assets investment, the implementation of the national revitalization of equipment manufacturing strategy and other favorable factors, and the whole industry has been developing development. According to the statistics of Pile Machinery Branch of China Construction Machinery Industry Association, in 2012, the sales volume of pile machinery in China was 10 billion yuan, and the sales volume was 6000 units. Although the output value of China can not catch up with Germany, Italy and other countries, but the number has been the first in the world.
1.1 Rotary drilling rig
At present, rotary drilling rig has been widely used in the construction of cast-in-place piles at home and abroad, especially in Europe and Japan and other developed countries, it has become the main equipment for the construction of large-diameter bored piles.
Production rotary drilling rig started in the 1980s, in 1988 Beijing urban construction engineering machinery factory developed the crawler crane attached rotary drilling rig, the mid-1990s Zhengzhou survey machinery co., LTD from the BSP introduced attached rotary drilling rig production technology, but because of the technology is relatively backward, form a complete set of crane coordination difficulties, no mass production. In 1998, XCMG Group successfully developed the first real rotary drilling rig in China, but it was limited by the domestic engine, hydraulic parts, drill pipe, power head and other accessories and use, and there was no mass production. Before 2003, China's rotary drilling RIGS are mainly imported, expensive, only a few strength of the foundation construction enterprises to buy. On the one hand, the construction of the Qinghai-Tibet Railway shows the performance of the rotary drilling rig, and on the other hand, it also reminds the domestic manufacturers that the basic construction machinery also has a lot of space for development. Then some companies have developed rotary drilling rig, such as Beijing scrane, Beijing CSR, Hunan was intelligence, futian heavy industry, etc., domestic rotary drilling rig development success greatly reduced the price of the rotary drilling rig, broke the import of the world, make more users afford rotary drilling rig, and by buying rotary drilling rig has achieved good economic benefits, the complementary relationship greatly promoted the application of rotary digging method in our country.
During the "11th Five-Year Plan" and "12th Five-Year Plan" period, China invested heavily in the construction of railway, highway, electric power and urban public facilities, especially the construction of high-speed rail has brought great opportunities for the development of China's rotary drilling RIGS. More than 80% of the high-speed railway passenger dedicated lines are Bridges, and the diameter of the bridge piles is mostly below 1.5m, and the depth is within 60m, which is just suitable for the construction of rotary drilling rig.
After the development of recent years, the main performance of the domestic rotary drilling rig machine has been close to or reached the international high level. At present, China has been able to produce a variety of specifications from 6 tm to 40 tm. According to the market needs, the small rotary drilling rig developed by Shandong Xinguo Heavy Machinery, Zhengzhou Chuandao and Zhejiang Zhenzhong medium Company has achieved very good performance in the field of pile foundation construction, with small rotary digging accurate positioning, low use cost, convenient maintenance and fast return, which is very suitable for small construction units. The large rotary drilling RIGS developed by CSR, XCMG, Sany and other companies are applied in the construction of large bridge pile foundation in the Yangtze River and the Yellow River, which greatly improves the construction efficiency and shortens the construction period. Since 2006, domestic rotary drilling RIGS have occupied the domestic market. According to the statistics of pile machinery branch, the sales volume of rotary drilling rig in China in 2006 was about 350 sets, about 450 in 2007, about 900 in 2008,1200 in 2009, and 1700 in 2010. At present, China has been the world's largest producer and user of rotary drilling RIGS.
Although the broad market prospect provides market opportunities for China's rotary drilling rig enterprises, but compared with the development of foreign rotary drilling rig enterprises, the domestic rotary drilling rig industry started late, and a large number of application in the market for a long time, so the domestic equipment needs to be improved can not be ignored. First of all, China's rotary drilling rig variety is single, most manufacturers only produce one or two specifications of products, should produce a variety of product types. Secondly, there are few domestic independent innovation products. Third, the selection of imported accessories is single, which should be further diversified, and the level of after-sales service should be gradually strengthened. Fourth, the quality of domestic accessories such as drill pipe and tools should be further improved. Fifth, the research of the supporting process of rotary drilling rig construction is not enough. China has a vast territory and complex geological conditions. According to different geological types, different construction schemes and suitable construction equipment should be clearly defined. For example, the strata in the southeast coast are soft, most of the strata in the southwest and northwest are complex, and the new Line is basically pebble layers. How to form holes and improve the construction efficiency in these areas requires great efforts to study, and only the main engine cannot solve the problem.
1.2 Long screw rig
In small diameter (below 800mm) small depth (30m) concrete pile construction, long screw rig has advantages, high efficiency, low cost, especially after in recent years, CFG pile and the development of steel cage technology success greatly improve the scope of long spiral bored pile, has now from the north China to Hubei, Hunan, Guangdong and other places. Some sections of high-speed railway passenger dedicated line use CFG piles for subgrade reinforcement, which also drives the production of long spiral RIGS. In recent years, the output of long spiral RIGS has increased steadily. According to the statistics of several major manufacturers, in 2012,363 hydraulic walking long screw drillers, and 178 electric and hydraulic crawler long screw drillers were produced. The above statistics are not comprehensive. According to the production situation of long screw rig power head, the output of older screw drilling rig in 2011 should be close to 1000, and about 1500 in 2012. Now China has formed Zhengzhou, Xinhe, Jiaodong, Ruian, Changsha several large long screw rig production bases.
The manufacturer and output of long screw rig are many, but the product performance of each factory is not different, and the rig power head and drill tool of each manufacturer are almost the same. The construction method of long screw rig used in China is relatively single, Japan by the deformation of long screw rig is very much, China's manufacturers and construction out of line, the improvement of equipment for many years progress is not much. In fact, long screw rig chillers still have a lot of room for development.
1) Develop the casing long screw drilling rig suitable for soft soil, pebble layer and other complex collapse strata, that is, the built-in drill pipe with high speed and small torque rotation, and the outer casing with low speed and large torque reversal.
2) The drilling rig power head develops from single speed to multiple speed to meet the requirements of different pile diameter and depth and improve the construction efficiency.
3) Drill tools directly affect the construction efficiency of the long screw drilling rig. The manufacturer should combine with the construction unit to develop drilling tools suitable for different geological conditions. Foreign
4) The product lacks necessary safety devices, such as pile pulling force limiter, anti-rolling device, etc., with poor stability and frequent accidents.
1.3 Positive and reverse cycle engineering drilling rig
Although rotary drilling rig development is fast, but in the southeast coastal areas and other small and medium-sized cities of concrete pile construction is still mainly given priority to with positive circulation engineering drilling rig, positive circulation engineering drilling rig construction need mud wall protection, produce a lot of mud, many construction enterprises of mud without any treatment random discharge cause serious environmental pollution. With the improvement of China's economic level, the sound of environmental regulations and the application of new equipment, the use of this rig will be less and less. Of course, in the construction of large diameter (above 2m) and large depth (over 60m) pile foundation, the positive and reverse circulation engineering drilling machine still has advantages. In recent years, the output of positive and reverse cycle engineering drilling RIGS has changed little, with about 1000 units every year.
In the construction of the foundation pile across the river and the sea, there is still a gap between the domestic large diameter positive and reverse cycle engineering drilling rig and the imported drilling rig, such as many faults, low rock efficiency, easy to damage. In recent years, there are many projects on the sea river in China, and domestic manufacturers should tackle the key problems in this respect.
In some areas of China, such as Wenzhou, Ningbo and other places, the soil is particularly soft, mainly silt, the pile side friction is very small, the pile must be put into the rock. China's rock entry equipment is very backward, now the small and medium diameter rock-embedded pile basically use impact drill construction, but the efficiency is very low. Foreign submersible hammer is usually used to construct rock strata, the efficiency is very high, but the domestic large diameter submersible hammer is still blank, and the reliability of small diameter submersible hammer is very poor, which needs further study.
1.4 Hydraulic and static pile press
At present, the construction equipment of pipe pile is mainly hydraulic static pile press, its advantages are no vibration, no noise, no pollution and good quality, so concrete precast pipe pile is a construction method that has been promoted rapidly in China in recent years. At present, from the south to the north, from the coastal area to the inland of most provinces and cities have been applied, especially in the soft soil area has become the pile type of industrial and civil construction. The main reasons are given as follows:
1) Pipe pile processing in the factory, the quality is easy to ensure, unlike the site cast-in-place pile is prone to quality accidents;
2) The scale of pipe pile production enterprises is getting bigger and bigger, and the cost of pipe pile is greatly reduced;
3) The performance of the hydraulic static pile press has been significantly improved, and the product types are becoming more and more rich;
4) The vigorous promotion of pipe pile production enterprises and pile press production enterprises.
In 2012, China produced more than 600 sets of hydraulic static pile press. The production enterprises of hydraulic static pile press are mainly concentrated in Hunan, Zhejiang, Shanghai, Jiangsu, with a market share of more than 50%. In view of the problem of difficult construction of hard formation static pile press, Shanhe Intelligence and Guangdong Institute of Construction Science are jointly developing the static pile press with the drill, that is, using the screw drill in the pile pipe to drill and press the pile to reach the predetermined depth, the drill is reversed, the reaming drill is recovered, and the drill pipe is pulled out from the pile pipe. The disadvantages of hydraulic static pile press are heavy, high transportation costs and trouble to transfer the site.
1.5 Pile hammer
Pile hammer includes cylinder diesel hammer, guide rod diesel hammer, hydraulic hammer, vibrating hammer, etc.
The main manufacturers of cylinder diesel hammer are Shanghai Construction Machinery Factory, Guangdong Liyuan Hydraulic Machinery Co., LTD. The main production plants of guide rod diesel hammer are Jiangsu Dongda, Juli, Juwei, Fushun 6409 and so on. Among them, Shanghai Construction Machinery Factory introduced technology from Germany Delmak, good quality, large batch, in order to cooperate with the construction of Shanghai Yangshan Port and Hangzhou Bay Bridge, Donghai Bridge wind power, the plant developed D160, D220 diesel hammer. Diesel hammer due to noise, lampblack pollution and other public hazards can not be solved, the use will be less and less.
The main manufacturers of vibrating hammer are Zhejiang Zhenzhong Construction Machinery Co., Ltd., Zhejiang Ruian Bada Construction Machinery Factory, etc. The development of electric vibrating hammer in China has been very mature, from a few kilowatts to hundreds of kilowatts can be designed and manufactured by themselves. In recent two years, the adjustable eccentric torque vibration hammer of Zhejiang Zhenzhong Company has been used in the sand pile project of Shanghai Yangshan Port, and exported to Japan, South Korea and other developed countries. China's hydraulic vibrator has just started, Shanghai Zhenzhong has developed 100t, 200t hydraulic vibrator. Hydraulic vibrating hammer should develop in the direction of high frequency and frequency modulation and amplitude modulation.
In the next few years, China will invest trillions of dollars to build offshore wind power. In the past, offshore wind power foundation were mostly pile construction, with long construction cycle and high cost. The offshore wind power under construction in Europe, Japan and other countries has been changed to a single pile foundation, that is, the large steel pipe with a diameter of 5~6m, a wall thickness of about 100mm and tens of meters long is directly driven with hydraulic impact hammer or sunk to the seabed with vibrating hammer. This kind of large hydraulic hammer or vibrating hammer in China is still blank, must be imported from abroad, and the price of imported products is very expensive. Combined with the needs of the project, the domestic strong enterprises should start to study.
1.6 Hydraulic grab bucket
In the past ten years, underground continuous wall technology has developed rapidly. Shanghai, Guangzhou, Beijing and other places have applied underground continuous wall support technology in hundreds of projects such as high-rise buildings and subway stations. It is understood that The State Council has approved the construction of more than 20 subway and light rail in cities, with an investment of nearly one trillion yuan, China's underground continuous wall construction equipment will certainly have a big development. At present, the equipment used in building underground continuous wall in China is hydraulic grab bucket and multi-axis drilling machine.
Build large depth large thickness underground continuous wall usually use grab type into slot machine, mainly including wire rope grab, hydraulic guide plate grab, guide rod grab, mixed grab, etc., due to the hydraulic guide plate grab with grab lift speed, closed bucket force, strong digging ability, high construction efficiency, construction depth, into wall thickness, a wall into high precision (automatic correction device), so the largest usage. In recent years, domestic hydraulic grab has developed rapidly. In 2012, the sales volume of hydraulic grab in China was about 120 sets, and the production enterprises include Shanghai Jintai, Xugong, CSR, Sany, Shanghai Engineering, etc. At present, Shanghai Jintai's hydraulic grab market share is more than 50%。
1.7 Multi-axis drill machine
SMW method is to use a special multi-axis drilling machine (generally 3 axes) to cut the soil, and at the same time to inject the cement slurry into the soil at the drill end. After full mixing, H-steel or other profiles are inserted into the mixing pile to form an underground continuous wall. The wall is directly used as the retaining and water stop structure. This method replaces the original retaining method of bored pile and water retaining curtain, which has the advantages of fast construction speed, good water retaining effect, low project cost, no pollution and so on, and is a promising construction technology. SMW method has been popularized and used in Shanghai, Tianjin, Nanjing, Hangzhou and other places.
In the early stage, the multi-shaft drilling machine for SMW construction was imported from Japan all the time, such as Japanese Sanhe machine materials and Sanhe mechanics, mainly two mobile phones, which were expensive. The shortage of equipment seriously restricted the promotion and application of SMW method in China. In recent years, the domestic SMW drilling machine with multi-axis drilling machine has been able to meet the needs of domestic construction. The main production enterprises are Shanghai Engineering, Shanghai Jintai and Zhejiang Zhenzhong. In 2012, the sales volume of SMW drilling multi-axis drilling machine is about 130 sets. This year, Shanghai Construction Machinery Factory has developed an ultra-depth multi-axis drilling rig with a construction depth of more than 50m according to the needs of the project, which is very well used in the foundation pit construction of Zhengzhou high-speed railway station.
1.8 Pile frame
Pile frame is a customary name, according to its use and construction principle, in fact, is a piling special lifting and guidance equipment. Diesel hammer, hydraulic hammer, vibrating hammer, drilling machine, vibrating machine, deep mixer and other working devices must be used with pile frame during the construction. The function of pile frame is mainly to lift various pile hammer and other working devices, pile hopper, steel cage, etc., and to guide and change of pile hammer and other working devices (inclined pile) to determine the pile position.
Pile frame is divided into rolling pipe type, track type, track type, track type and track type. At present, the pile frames widely used in China are rolling pipe type and walking type. This kind of pile frame has been rarely used internationally. Hydraulic walking pile frame is a pile frame with Chinese characteristics. It moves pile position and rotation, with low cost and is welcomed by small and medium-sized foundation construction companies. Its disadvantage is the inconvenience of transfer. Full hydraulic crawler three-point pile frame is a kind of pile frame widely used abroad. Shanghai Construction Machinery Factory has introduced the production technology of Japanese vehicles DH 558 and DH 658 pile frame.
In the late 1990s, some manufacturers in China developed the advantages of electric crawler pile frame combined with the advantages of walking pile frame and crawler pile frame, the cost is greatly reduced compared with the full hydraulic crawler pile frame, and the movement is more convenient than walking frame. The product is welcomed by the construction unit and is the development direction of crawler pile frame in the short term, but there are hidden dangers in its external power supply.
2 Pile engineering machinery products that need to be studied in China
2.1Construction equipment of underground continuous wall
The underground continuous wall includes load-bearing continuous wall, seepage proof retaining wall and simple seepage proof wall. The underground continuous wall construction of general strata uses hydraulic grab, but the construction is difficult, so Bao'e and Casa Grandi Company have developed the horizontal multi-axis cutting machine, introduced the above equipment in the Three Gorges Project, the South-to-north Water Diversion Project, Shenzhen Metro and Shanghai Metro, and the use effect is very good.
In the field of anti-seepage retaining wall (cement wall) construction, vertical single axis or multi axis rig was used in the coastal SMW method of Japan and China. However, the current multi-axis drilling rig is difficult in the construction of hard and complex strata, such as the construction of the three-axis drilling rig in Beijing. In order to solve this problem, German Boe company developed BCM series horizontal multi-axis deep mixer, and Japanese Kobelco company developed TRD cutting machine. Bao'e BCM series horizontal multi-axis deep mixer lower part has two horizontal set cutting head, cutting head inlaid with teeth, the upper is a square guide rod, through the slide and three fulcrum pile driver column connected. The machine is adapted to a wide surface, in the rock, gravel layer can be constructed, the construction depth can reach 35m, high construction accuracy, the wall waterproof effect is good, no pollution. In Kobels TRD cutting machine structure, a sprocket chain cutting mechanism is arranged on the side of the crawler chassis, with a cutting head on the surrounding chain. Different from the previous longitudinal construction methods, TRD cutter began to drill to a predetermined depth, and then full depth transverse cutting, cutting simultaneously injected cement slurry to form a cement wall. The construction efficiency of TRD cutting machine is very high, the actual depth of construction has reached 60m, the wall quality is good, no pollution.
2.2 Underground obstacle removal equipment
With more and more projects of the old city reconstruction, how to dismantle the underground foundation of the old buildings is a difficult problem. The venues of the 2010 Shanghai World Expo were all built on the original factories on both sides of the Huangpu River, and there are similar problems. Now China adopts the method of vibration and high pressure flushing. In Japan and other developed countries, there are many old city reconstruction projects, and a variety of construction methods and equipment have been developed to remove underground obstacles. Generally, the full set of pipe rotary drill cutting, and the obstacles cut in the casing mainly have three removal ways: ① with the bucket, cross hammer crushing; ② electric or hydraulically driven short screw bits broken and removed; ③ multi-claw hydraulic crushing machine crushing.
2.3 Long screw drilling rig rock entry equipment
At present, in order to ensure the bearing capacity of many pile foundations, piles are required to enter the rock. The rock entry equipment used in China is very backward, basically impact drilling, with low efficiency and serious mud pollution. In countries such as Korea and Japan, there is a construction method of rock entry construction, that is, the joint construction of double power head long screw drill and pneumatic submersible hole hammer. The specific method is: the internal power head drives the long screw drill pipe, the bottom of the drill pipe is equipped with the submersible hole hammer, the drill pipe drives the submersible hole hammer back at the same time, the high-pressure air through the internal hole of the drill rod drives the head of the submersible hole hammer up and down, so that the side turns and impact, the rock is broken into small pieces. As the external power head drives the outer back, the rock broken into small pieces is returned to the ground along the spiral blade under the action of high-pressure air. After reaching the predetermined depth, pull out the inner drill pipe and the submersible hole hammer, and then pull out the outer pipe after inserting the steel cage. This kind of construction method has high construction efficiency, good hole-forming quality, and no mud pollution.
3 Main questions and suggestions
1) Develop new products in combination with construction method. Pile machinery is characterized by: to meet different piles, different geological conditions and different engineering requirements, and with the construction method, and need to develop new varieties, so the pile machinery industry each equipment has their own range, is in the rapid development, the enterprise must seize the opportunity, lay the foundation, set.
2) Strengthening independent innovation, improving the performance of traditional products, and using high and new technology to transform and enhance traditional products are important measures to improve the competitiveness of the industry.
3) Improve the core competitiveness, and enter the world with independent innovation. In recent years, China's pile machinery export situation is encouraging, but there is still a certain gap between the world's advanced level, to create a stable market share and brand, enterprises must raise products, accessories, services to a certain height, which is the basic guarantee to achieve international development.
4) Avoid disorderly competition and advocate harmony and win-win situation. The development strategy of the enterprise should be the common development among the stakeholders. The enterprise should combine the national conditions and the characteristics of engineering construction, constantly make independent innovation, seriously study the market, so that each enterprise has its own characteristics and brand, form a differentiated competition pattern, and walk out of a steady development path suitable for itself.(Source: Huicong Construction Machinery Network)
