A construction technology for the base bed of a gravity-type wharf approach embankment near a mountain

Abstract

The present invention discloses a construction process for the base bed of a gravity-type wharf approach embankment adjacent to a mountain. The process is divided into three sections. The rock surface elevation of the base section of the approach embankment is above +3.0m. The rock surface elevation of the reef in the middle section of the approach embankment decreases from +3m to -6m along the shore. The rock surface elevation of the reef in the starting section of the approach embankment decreases from -6.0m to -12m along the shore. The base bed construction process of the starting section of the approach embankment adopts underwater reef blasting. The base bed construction process of the base section of the approach embankment adopts a combined onshore shallow-hole and deep-hole blasting process. The base bed construction process of the middle section of the approach embankment first uses rock filling and leveling to form a construction platform with an elevation of +3.0m in the area below +0m. A hydraulic down-the-hole drill is then used on the construction platform to sequentially drill the guide hole for the rock overburden layer, drill the bedrock hole, and then blast. The present invention solves the problem that conventional onshore and underwater reef blasting processes cannot be used in the middle section of the approach embankment.

Description

Technical Field

[0001] The invention relates to a construction process for a gravity-type wharf approach embankment base bed adjacent to a mountain. Background Art

[0002] The ocean is a valuable asset for sustainable development and is of great significance to human survival and development. Marine ports are powerful engines for marine economic and social development, providing reliable support for transitioning from the mainland to the ocean and enhancing international competitiveness. Therefore, port construction will continue to play a crucial role in future infrastructure development. Jetty-type piers, with their ability to fully utilize shoreline resources, offer broad prospects for construction. During pier construction, the first step is the construction of the pier approach embankment, which serves as a connecting channel between the pier platform and the rear road. For gravity-type piers, the pier approach embankment's base bed must be constructed first. A plan view of a site reveals that the foundations of the first four caissons of the approach embankment section are fully embedded in the mountain. The natural rock face at the end of the approach embankment extends from +20m down the shore to -12m below the seabed, creating a steep bank. At present, there are some relatively mature technical cases for solving the problem of blasting and excavating underwater foundations of hydraulic structures adjacent to mountains in the construction of water transport projects such as open water intake channels and docks at home and abroad. However, these cases are only applicable to solving small-area, small-volume, and long-term blasting projects of foundations adjacent to mountains. None of them can be applied to the excavation of gravity caisson foundations of large-scale guide embankments adjacent to mountains. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects of the existing technology and provide a construction process for the gravity-type wharf embankment base bed adjacent to the mountain. It is convenient for construction and can solve the problem of reef excavation of large-scale adjacent mountain base beds that cannot be achieved by conventional onshore blasting technology and underwater reef blasting technology of reef blasting ships.

[0004] The object of the present invention is achieved by providing a construction process for the foundation of a gravity-type wharf approach embankment adjacent to a mountain, wherein the construction is carried out in three stages, namely, the foundation construction process of the initial stage of the approach embankment, the foundation construction process of the middle stage of the approach embankment, and the foundation construction process of the root stage of the approach embankment; the root stage of the approach embankment is embedded in the mountain rock and the rock surface elevation is above +3.0m, which is higher than the designed high water level; the reef rock surface elevation of the middle stage of the approach embankment decreases from +3m to -6m along the bank; the reef rock surface elevation of the initial stage of the approach embankment decreases from -6.0m to -12m along the bank;

[0005] During the construction process of the base bed of the starting section of the guide dike, a reef blasting ship equipped with multiple fully hydraulic drilling machines is used for underwater reef blasting construction; the reef blasting ship adopts the anchoring positioning method, that is, a side cable is arranged on the left and right sides of the front and left and right sides of the rear of the reef blasting ship, a main cable is arranged in the middle of the front and the middle of the rear of the reef blasting ship, and two ground cages are set up on the shore, which are connected one by one with a side cable at the front and a side cable at the rear of the reef blasting ship; the reef blasting ship adopts the RTK positioning system to accurately determine the position of the blasthole, and the underwater reef blasting is promoted from the sea side to the shore side; the reef blasting ship first lowers the casing before drilling the blasthole, and then lowers the drill tool along the casing to drill the blasthole. During the drilling process, the drill rod is lifted and air and water are blown to discharge the debris in the blasthole out of the hole; the blasthole drilling After reaching the designed depth, the drill rod is repeatedly lifted and lowered to prevent gravel from clogging the blasthole; after each blasthole is drilled, the drill rod is pulled out and the explosives and detonator are loaded into the blasthole along the casing using a charging rod, and the explosives are compacted with a gun stick before the casing is pulled out; after the blastholes at each ship position are drilled, the explosives are also loaded, and the elevation error of the blasthole bottom is no more than 50cm; the blastholes are blocked with fine sand and gravel, and the blocking length is no less than 50cm; 2 or 4 detonators are loaded into each hole according to the depth of the blasthole, and the detonators in each blasthole are connected to the main detonator according to the designed detonation network. The main detonator is connected in series with several detonators to the detonator according to the length requirements; the detonator is installed on the reef blasting ship, and the reef blasting ship is sailed to a safe distance by winching before detonation;

[0006] During the construction process of the base bed of the root section of the approach dike, a combination of shallow hole blasting and deep hole blasting using a down-the-hole drill was adopted;

[0007] Shallow hole blasting is used at the end because the rock layer is above +3.0m, and the mountain is gradually decomposed by blasting; the design parameters of shallow hole blasting are:

[0008] Drilling diameter: φ42mm; Step height: H = 1m ~ 4m; Minimum resistance line: W ≤ 1.5m; Hole spacing: a = (1 ~ 1.2)W; Row spacing: b = (0.9 ~ 1.0)W; Extra deep: h = 0.3 ~ 1.0m; Drilling depth: L = H + h; Unit explosive dosage: q = 0.25 ~ 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; single hole charging amount: Q = qabH;

[0009] The root section of the dike is located in a mountain rock layer below +3.0m. Since the surrounding area has been completely backfilled, it must be blasted in one go. Therefore, deep hole blasting is adopted at different distances. The design parameters of deep hole blasting are as follows:

[0010] Drilling diameter: φ90mm; step height: H = 1m to 14m; minimum resistance line: W ≤ 1.5m; hole spacing: a = (1 to 1.2)W; row spacing: b = (0.9 to 1.0)W; extra-deep: h = 0.3 to 1.0m; drilling depth: L = H + h, vertical downward drilling is adopted; unit consumption of blasting explosives: q = 0.25 to 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; single hole charging amount: Q = qabH;

[0011] The construction process of the base bed in the middle section of the approach dike includes the following steps:

[0012] Step 1: Fill and level the area below the +0m rock surface with rubble to form a construction platform at a +3.0m elevation. The rubble used for the filling is the slag generated during the construction of the base bed at the root of the approach dike.

[0013] Step 2: Use a hydraulic down-the-hole drill to construct a steel casing hole in the rock overburden layer on the construction platform; the drilling tools of the down-the-hole drill include a center drill bit, an eccentric drill bit, a pipe shoe, a guide and a drill rod; the pipe shoe is made of heat-treated pipe with a wall thickness of 8mm; the wall thickness of the steel casing connected to the pipe shoe is also 8mm; after the down-the-hole drill reaches the predetermined hole-guiding position, the pipe shoe is put on the eccentric drill bit and mechanically connected to the steel casing, and then the eccentric drill bit is upright to the rock overburden layer and drilling begins; the down-the-hole drill cuts the rock overburden layer through the eccentric drill bit, and drives the pipe shoe and steel casing to pass through the rock overburden layer; as each section of steel casing follows up When the top is 15cm to 20cm away from the surface of the block rock cover, stop drilling and take over the pipe; the length of each subsequent steel casing section is 1.5m to 2.0m, and then continue drilling; when the drilling rate of the eccentric drill bit slows down significantly and the drilling difficulty increases, compare the drilling depth of the steel casing with the original designed rock surface elevation to determine whether the block rock cover has been penetrated and a channel for bedrock solid hole drilling has been formed; if not, continue drilling; if yes, continue drilling to 50cm of the original moderately weathered rock and then stop drilling to form a channel for bedrock solid hole drilling, and then move to the next guide hole point for drilling operations;

[0014] Step 3: After the bedrock hole drilling channel is completed, the drilling tool of the down-the-hole drill rig is replaced with an integrated drill rod, and the bedrock hole drilling is continued along the bedrock hole drilling channel to ensure that the drilling reaches 2.5m below the bottom elevation of the designed bed to form a bedrock blasting hole;

[0015] Step 4: After the drilling of each bedrock blasting hole is completed, explosives are promptly loaded into the bedrock blasting hole for blasting operations;

[0016] Step 5: After the blasting of all the mileage in the middle section of the guide dike is completed, a grab dredger is used to carry out offshore reef clearing construction at the starting section of the guide dike; two long-arm excavators are used to excavate the foundation trench of the middle section of the guide dike and the root section of the guide dike from the sea side to the shore side, and the excavated reefs are transported out by dump trucks; after the base bed excavation is completed, the sea is swept immediately, and rock drills or dredgers are used to carry out secondary reef clearing in areas where excavation is insufficient.

[0017] In the above-mentioned construction process of the base bed of the gravity-type wharf approach embankment adjacent to the mountain, when carrying out step 2 of the base bed construction process of the middle section of the approach embankment, the approach holes are arranged with a row spacing of 2.5m and a hole spacing of 2m, and the holes are arranged in a plum blossom shape.

[0018] In the above-mentioned construction process for the base bed of the gravity-type wharf approach embankment adjacent to the mountain, in step 4 of the base bed construction process for the middle section of the approach embankment, an emulsion explosive with a diameter of 90 mm is used. The explosive is loaded into the bottom of the bedrock blasting hole using a charging rod, and then coarse sand is used to block the hole, with a blocking length of 1 m. The standard charge Q for a single hole is calculated according to the following formula: Q = qH, where q is the basic charge kg / m 3 ; H is the thickness of the rock layer in m; a digital electronic detonator blasting network is also used, and a millisecond difference delay blasting sequence is adopted, with the delay blasting between holes being 50 to 75 ms and the delay blasting between rows being 75 to 110 ms.

[0019] The construction process of the base bed of the gravity-type dock embankment adjacent to the mountain of the present invention has the following characteristics: according to the geological conditions of the dock embankment where the bedrock is exposed, the rock surface changes violently, it has been eroded by waves for a long time, cracks are developed, and there is a small-scale rock collapse, the construction is divided into three sections, that is, the base bed of the outermost starting section of the embankment adopts the underwater reef blasting process of the reef blasting ship; the root section of the innermost part of the embankment adopts the process of combining onshore shallow hole blasting and deep hole blasting; in the middle section of the embankment, since the original reef rock surface elevation is -6.0m to +3.0m, it is all located below the designed high water level, and the conventional onshore blasting process cannot be implemented. At the same time, the embankment is affected by the blasting of the base bed. The working space in the foundation pit is limited, and there are many reefs on the adjacent shore, so the reef blasting ship cannot be stationed. Therefore, the reef blasting ship cannot be used for underwater reef blasting. Therefore, the middle section of the guide dike first uses block stones to an elevation of +3.0m to form a construction platform. Then, a down-the-hole drill is used on the construction platform to drive the steel casing to drill holes, forming a channel for bedrock solid hole drilling. Then, bedrock solid holes are drilled along the bedrock solid hole drilling channel to form bedrock blasting holes, and then blasting excavation is carried out to form the base bed. This not only facilitates construction, but also effectively solves the problem of reef excavation in the middle section of the guide dike, which cannot be achieved by conventional onshore blasting technology and underwater reef blasting technology of reef blasting ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a plan view of the guide embankment involved in the construction process of the base bed of the gravity-type pier near a mountain in the present invention;

[0021] Figure 2 It is a cross-sectional view of the guide embankment involved in the construction process of the base bed of the gravity-type pier near the mountain in accordance with the present invention;

[0022] Figure 3 It is a cross-sectional view of step 1 of the base bed construction process of the middle section of the dike in the construction process of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] See also Figure 1 and Figure 2 The construction process of the base bed of the gravity-type wharf embankment adjacent to a mountain of the present invention is divided into three sections, namely, the base bed construction process of the starting section of the embankment, the base bed construction process of the middle section of the embankment, and the base bed construction process of the root section of the embankment; the length of the root section 30 of the embankment is 8.63m, and the root section 30 of the embankment is embedded in the mountain rock and the rock surface elevation is above +3.0m, which is higher than the designed high water level; the length of the middle section 20 of the embankment is 42m, and the reef rock surface elevation of the middle section 20 of the embankment drops from +3m along the shore to -6m; the length of the starting section 10 of the embankment is 25.56m, and the reef rock surface elevation of the starting section 10 of the embankment drops from -6.0m along the shore to -12m.

[0025] During the construction process of the base bed of the starting section of the guide dike, a reef blasting ship equipped with multiple fully hydraulic drilling machines is used for underwater reef blasting construction; the reef blasting ship 100 adopts the anchoring positioning method, that is, a side cable 102 is arranged on the left and right sides of the front and the left and right sides of the rear of the reef blasting ship 100, and a main cable 101 is arranged in the middle of the front and the middle of the rear of the reef blasting ship. Because it is close to the shore, two ground cages are set on the shore to facilitate the positioning of the reef blasting ship. The two ground cages are connected one by one to a side cable 102 at the front and a side cable 102 at the rear of the reef blasting ship 100; the reef blasting ship adopts the RTK positioning system to accurately determine the position of the blasthole, and the underwater reef blasting is promoted from the sea side to the shore side; the high drill frame "one pipe and one drill method" is adopted, and the high drill frame is used to overcome the influence of the tidal difference on the drilling. The reef blasting ship first lowers the casing before drilling the blasthole, and then lowers the drill tool along the casing to drill the blasthole. During the drilling of the blasthole, the drill rod is lifted and the drilling tool is lowered. Air and water are blown to discharge the debris in the blasthole out of the hole; after the blasthole is drilled to the designed depth, the drill rod is repeatedly lifted and lowered to prevent the blasthole from being blocked by gravel; in order to prevent the hole from being blocked by gravel and sediment from silting up, each blasthole is loaded immediately after drilling, that is, after the drill rod is pulled out, the explosives and detonator are loaded into the blasthole along the casing using a charging rod, and the explosives are compacted with a gun stick to ensure the quality of the charge, and then the casing is pulled out; after the blasthole is drilled at each ship position, the explosives are also loaded, and the elevation error of the blasthole bottom of the loaded charge is not more than 50cm; the blasthole is blocked with fine sand and gravel, and the blocking length is not less than 50cm; 2 or 4 detonators are loaded into each hole according to the depth of the blasthole, and the detonators in each blasthole are connected to the main detonator according to the designed detonation network, and the main detonator is connected in series with several detonators to the detonator according to the length requirement; the detonator is installed on the reef blasting ship, and the reef blasting ship is sailed to a safe distance by winching before detonation;

[0026] During the construction process of the base bed of the root section of the approach dike, a combination of shallow hole blasting and deep hole blasting using a down-the-hole drill was adopted;

[0027] Shallow hole blasting is used at the end because the rock layer is above +3.0m, and the mountain is gradually decomposed by blasting; the design parameters of shallow hole blasting are:

[0028] Drilling diameter: φ42mm; Step height: H = 1m ~ 4m; Minimum resistance line: W ≤ 1.5m; Hole spacing: a = (1 ~ 1.2)W; Row spacing: b = (0.9 ~ 1.0)W; Extra deep: h = 0.3 ~ 1.0m; Drilling depth: L = H + h; Unit explosive dosage: q = 0.25 ~ 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; single hole charging amount: Q = qabH;

[0029] The root section of the dike is located in a mountain rock layer below +3.0m. Since the surrounding area has been completely backfilled, it must be blasted in one go. Therefore, deep hole blasting is adopted at different distances. The design parameters of deep hole blasting are as follows:

[0030] Drilling diameter: φ90mm; step height: H = 1m to 14m; minimum resistance line: W ≤ 1.5m; hole spacing: a = (1 to 1.2)W; row spacing: b = (0.9 to 1.0)W; extra-deep: h = 0.3 to 1.0m; drilling depth: L = H + h, vertical downward drilling is adopted; unit consumption of blasting explosives: q = 0.25 to 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; single hole charging amount: Q = qabH;

[0031] During the construction process of the base bed of the middle section of the guide dike, the elevation of the reef rock surface where the middle section 20 of the guide dike is located is -6.0m to +3.0m, which is below the design high water level. Conventional onshore blasting technology cannot be implemented. At the same time, due to the limited working space of the guide dike foundation trench and the large number of reefs on the adjacent shore, a reef blasting vessel cannot be stationed. Therefore, underwater reef blasting technology cannot be used by a reef blasting vessel. Therefore, the middle section of the guide dike first uses block stones to form a construction platform at an elevation of +3.0m. Then, a down-the-hole drill is used on the construction platform to drive the steel casing to drill a hole to form a channel for drilling a solid hole into the bedrock. Then, blasting excavation is carried out to form the base bed. The base bed construction of the middle section of the guide dike includes the following steps:

[0032] Step 1: Fill and level the rock surface below +0m with boulders to form a construction platform 200 with an elevation of +3.0m (see Figure 3 The rubble used for backfilling is the slag produced during the construction of the base bed at the root section of the dike. The particle size of the slag must be strictly controlled during the backfilling process. Excessive particle size will reduce the efficiency of subsequent borehole construction.

[0033] Step 2: On the construction platform 200, a hydraulic down-the-hole drill is used to construct a steel casing hole for the block stone covering layer; the drilling tools of the down-the-hole drill are a center drill bit with a diameter of 115 mm, an eccentric drill bit with a diameter of 152 mm, a pipe shoe with an outer diameter of 146 mm, a guide with a diameter of 115 mm and a drill rod with a diameter of 76 mm; the pipe shoe is made of a heat-treated pipe with a wall thickness of 8 mm; the outer diameter of the steel casing connected to the pipe shoe is 146 mm and the wall thickness is also 8 mm; an eccentric shaft is provided inside the center drill bit, and the upper part of the center drill bit is connected to the guide by a thread, and the eccentric drill bit is sleeved on the eccentric shaft of the center drill bit. On the shaft, one side of the center drill bit is provided with a flange for transmitting torque, and the flange is designed to have an inclined contact surface. During drilling, the eccentric drill bit is thrown out by the inertial force and the friction of the hole wall, rotates 180 degrees, is restrained by the flange, rises along the inclined surface, and presses against the guide, thereby transmitting the impact energy of the impactor to achieve the purpose of hole expansion. The inner wall of the pipe shoe is connected to the top of the eccentric drill bit by providing a raised inner tooth, which can smoothly achieve drilling follow-up. When drilling stops, the drill bit is reversed, and the eccentric drill bit retracts to the convergent position due to the friction of the hole wall and the pipe shoe. The drill bit is smoothly pulled out of the steel casing, thus completing the pipe follow-up drilling.

[0034] Since a new rock overburden has been added to the surface of the original bedrock where the middle section of the pilot dike is located, the bedrock blasting hole network needs to be densified. Therefore, the pilot holes (bedrock blasting holes) in the middle section of the pilot dike are arranged with a row spacing of 2.5m and a hole spacing of 2m, and the holes are arranged in a plum blossom shape. After the down-the-hole drill arrives at the predetermined pilot hole location, the pipe shoe is put on the eccentric drill bit and mechanically connected to the steel casing. The eccentric drill bit is then erected to the rock overburden layer and drilling begins. The down-the-hole drill uses the eccentric drill bit to cut the rock overburden layer, and drives the pipe shoe and steel casing to pass through the rock overburden layer to ensure that an effective retaining wall can be formed in the rock overburden layer. When each section of the steel casing is When the pipe is followed to the point where the top is 15cm to 20cm away from the surface of the block rock cover, stop drilling and take over the pipe; the length of each subsequent section of steel casing is 1.5m to 2.0m, and then continue drilling; when the drilling rate of the eccentric drill bit slows down significantly and the drilling difficulty increases, compare the drilling depth of the steel casing with the original designed rock surface elevation to determine whether the block rock cover has been penetrated to form a channel for bedrock solid hole drilling; if not, continue drilling; if yes, continue drilling to 50cm of the original moderately weathered rock and then stop drilling to form a channel for bedrock solid hole drilling, and then move to the next guide hole point for drilling operations;

[0035] Step 3: After the bedrock hole drilling channel is completed, the drilling tool is replaced with an integrated drill rod with a diameter of 115 mm. The bedrock hole is drilled along the bedrock hole drilling channel to ensure that the drilling reaches 2.5 m below the bottom elevation of the designed bed, forming a bedrock blasting hole.

[0036] Step 4: After the drilling of each bedrock blasting hole is completed, explosives should be loaded into the bedrock blasting hole in time for blasting operation to avoid blasting operation causing disturbance to the position of the formed bedrock blasting hole and affecting the hole formation and charging effect of the bedrock blasting hole; use emulsion explosive with a diameter of 90mm, and load the explosive into the bottom of the bedrock blasting hole with a charging rod, and then use coarse sand to block the hole, with a blocking length of 1m; the standard charge Q of a single hole is calculated according to the following formula: Q=qH, where q is the basic charge kg / m 3 ; H is the thickness of the rock layer in m; a digital electronic detonator blasting network is also used, and a millisecond delay blasting sequence is adopted, with the inter-hole delay blasting being 50 to 75 ms and the inter-row delay blasting being 75 to 110 ms;

[0037] Step 5: After the blasting of all the mileage in the middle section of the guide dike is completed, a grab dredger is used to carry out offshore reef clearing construction at the starting section of the guide dike; two long-arm excavators are used to excavate the foundation trench of the middle section of the guide dike and the root section of the guide dike from the sea side to the shore side, and the excavated reefs are transported out by dump trucks; after the base bed excavation is completed, the sea is swept immediately, and rock drills or dredgers are used to carry out secondary reef clearing in areas where excavation is insufficient.

[0038] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A construction process for the foundation of a gravity-type wharf approach embankment adjacent to a mountain, the construction being carried out in three stages, namely, the foundation construction process of the initial stage of the approach embankment, the foundation construction process of the middle stage of the approach embankment, and the foundation construction process of the root stage of the approach embankment; the root stage of the approach embankment is embedded in the mountain rock and the rock surface elevation is above +3.0m, which is higher than the designed high water level; the reef rock surface elevation of the middle stage of the approach embankment drops from +3m to -6m along the shore; the reef rock surface elevation of the initial stage of the approach embankment drops from -6.0m to -12m along the shore; the characteristics are: During the construction process of the base bed of the starting section of the guide dike, a reef blasting ship equipped with multiple fully hydraulic drilling machines is used for underwater reef blasting construction; the reef blasting ship adopts the anchoring positioning method, that is, a side cable is arranged on the left and right sides of the front and left and right sides of the rear of the reef blasting ship, a main cable is arranged in the middle of the front and the middle of the rear of the reef blasting ship, and two ground cages are set up on the shore, which are connected one by one with a side cable at the front and a side cable at the rear of the reef blasting ship; the reef blasting ship adopts the RTK positioning system to accurately determine the position of the blasthole, and the underwater reef blasting is promoted from the sea side to the shore side; the reef blasting ship first lowers the casing before drilling the blasthole, and then lowers the drill tool along the casing to drill the blasthole. During the drilling process, the drill rod is lifted and air and water are blown to discharge the debris in the blasthole out of the hole; the blasthole drilling After reaching the designed depth, the drill rod is repeatedly lifted and lowered to prevent gravel from clogging the blasthole; after each blasthole is drilled, the drill rod is pulled out and the explosives and detonator are loaded into the blasthole along the casing using a charging rod, and the explosives are compacted with a gun stick before the casing is pulled out; after the blastholes at each ship position are drilled, the explosives are also loaded, and the elevation error of the blasthole bottom is no more than 50cm; the blastholes are blocked with fine sand and gravel, and the blocking length is no less than 50cm; 2 or 4 detonators are loaded into each hole according to the depth of the blasthole, and the detonators in each blasthole are connected to the main detonator according to the designed detonation network. The main detonator is connected in series with several detonators to the detonator according to the length requirements; the detonator is installed on the reef blasting ship, and the reef blasting ship is sailed to a safe distance by winching before detonation; During the construction process of the base bed of the root section of the approach dike, a combination of shallow hole blasting and deep hole blasting using a down-the-hole drill was adopted; Shallow hole blasting is used at the end because the rock layer is above +3.0m, and the mountain is gradually decomposed by blasting; the design parameters of shallow hole blasting are: Drilling diameter: φ42mm; step height: H=1m~4m; minimum resistance line: W≤1.5m; Hole spacing: a=(1~1.2)W; Row spacing: b = (0.9 ~ 1.0) W; Extra deep: h = 0.3 ~ 1.0m; drilling depth: L = H + h; unit explosive dosage: q = 0.25 ~ 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; single hole charging amount: Q = qabH; The root section of the dike is located in a mountain rock layer below +3.0m. Since the surrounding area has been completely backfilled, it must be blasted in one go. Therefore, deep hole blasting is adopted at different distances. The design parameters of deep hole blasting are as follows: Drilling diameter: φ90mm; step height: H=1m~14m; minimum resistance line: W≤1.5m; Hole spacing: a=(1~1.2)W; Row spacing: b = (0.9 ~ 1.0) W; Ultra-deep: h = 0.3 ~ 1.0m; drilling depth: L = H + h, vertical downward drilling; unit amount of blasting explosives: q = 0.25 ~ 0.40kg / m 3 , adjusted according to the on-site test explosion; filling length: Ls ≥ W; charging length: Lz = L-Ls; Single hole charge: Q=qabH; The construction process of the base bed in the middle section of the approach dike includes the following steps: Step 1: Fill and level the area below the +0m rock surface with rubble to form a construction platform at a +3.0m elevation. The rubble used for the filling is the slag generated during the construction of the base bed at the root of the approach dike. Step 2: On the construction platform, a hydraulic down-the-hole drill is used to construct a steel casing hole in the block stone covering layer; the drilling tools of the down-the-hole drill are a center drill bit, an eccentric drill bit, a pipe shoe, a guide and a drill rod; the pipe shoe is made of a heat-treated pipe with a wall thickness of 8mm; the wall thickness of the steel casing connected to the pipe shoe is also 8mm; after the down-the-hole drill reaches the predetermined hole-guiding position, the pipe shoe is put on the eccentric drill bit and mechanically connected to the steel casing, and then the eccentric drill bit is upright to the block stone covering layer and drilling begins; the down-the-hole drill cuts through the eccentric drill bit Cut the rock overburden and drive the pipe shoe and steel casing through the rock overburden. When each section of steel casing reaches 15cm to 20cm from the surface of the rock overburden, stop drilling and connect the pipe. The length of each subsequent section of steel casing is 1.5m to 2.0m, and then continue drilling. When the drilling rate of the eccentric drill bit slows down significantly and the drilling difficulty increases, compare the drilling depth of the steel casing with the original designed rock surface elevation to determine whether the rock overburden has been penetrated and a channel for solid drilling of the bedrock has been formed. If it does not meet the requirements, continue drilling; if it meets the requirements, continue drilling to 50 cm of the original medium-weathered rock and then stop drilling to form a channel for bedrock solid hole drilling, and then move to the next pilot hole point for drilling operations; Step 3: After the bedrock hole drilling channel is completed, the drilling tool of the down-the-hole drill rig is replaced with an integrated drill rod, and the bedrock hole drilling is continued along the bedrock hole drilling channel to ensure that the drilling reaches 2.5m below the bottom elevation of the designed bed to form a bedrock blasting hole; Step 4: After the drilling of each bedrock blasting hole is completed, explosives are promptly loaded into the bedrock blasting hole for blasting operations; Step 5: After the blasting of all the mileage in the middle section of the guide dike is completed, a grab dredger is used to carry out offshore reef clearing construction at the starting section of the guide dike; two long-arm excavators are used to excavate the foundation trench of the middle section of the guide dike and the root section of the guide dike from the sea side to the shore side, and the excavated reefs are transported out by dump trucks; after the base bed excavation is completed, the sea is swept immediately, and rock drills or dredgers are used to carry out secondary reef clearing in areas where excavation is insufficient.

2. The construction process of the guide embankment bed of a gravity-type wharf adjacent to a mountain according to claim 1 is characterized in that: During step 2 of the base bed construction process for the middle section of the approach dike, the approach holes are arranged with a row spacing of 2.5m and a hole spacing of 2m, and the holes are arranged in a plum blossom pattern.

3. The construction process of the base bed of the gravity-type wharf adjacent to a mountain according to claim 1 is characterized in that: During step 4 of the base construction process for the middle section of the dike, an emulsion explosive with a diameter of 90 mm is used. The explosive is loaded into the bottom of the bedrock blasting hole using a charging rod, and then blocked with coarse sand with a blocking length of 1 m. The standard charge Q for a single hole is calculated according to the following formula: Q = qH, where q is the basic charge in kg / m 3 ; H is the thickness of the rock layer in m; a digital electronic detonator blasting network is also used, and a millisecond difference delay blasting sequence is adopted, with the delay blasting between holes being 50 to 75 ms and the delay blasting between rows being 75 to 110 ms.

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