115 results about "Cave-in" patented technology

The invention discloses a composite seepage preventing structure for a large karst cave in a karst region and a construction method thereof, and belongs to the technical field of water conservancy and hydropower engineering. The composite seepage preventing structure comprises bed rock and the karst cave. The karst cave is located in the bed rock. The lower section of the karst cave is filled to form a karst filling area. A plurality of filling-material rotary jetting holes or steel pipe piles are vertically distributed in the karst cave filling area and arranged along the seepage preventing axis at intervals in a rowed mode. A transition cushion layer is arranged on the upper surface of the karst cave filling area. A concrete seepage preventing wall is arranged on the steel pipe piles. A cavity in the upstream side of the concrete seepage preventing wall is backfilled to form a backfilling area. According to the technical scheme, due to the reasonable construction method, the concrete seepage preventing wall is built in the karst cave, and the quite good partition effect and the quite good sealing effect are achieved through a karst cave roof joining groove structure in the top and a grouting-cave-aligning-grouting method; the structure and the method are simple, the quantity of input materials is small, construction intensity is small, construction efficiency is greatly improved, and the seepage preventing aim of large karst cave in the karst region is achieved.

The invention relates to an engineering pile in karst cave geology and a pile formation process. The lower part of the engineering pile passes through the geological layer, a cave is positioned in thegeological layer, the engineering pile passes through the karst cave and extends into anupper layer soil body; a circle of jet grouting pile reinforcing body is arranged on the outer wall of the engineering pile in the karst cave in a supporting way; the reinforcing body has a centrosymmetric structure; the cross section of the jet grouting pile reinforcing body is formed by a plurality of minorarcs which are connected with each other end to end; the geological layer sequentially comprises a limestone layer, a fractured rock layer and the upper layer soil body from bottom to top; the cave ispositioned in the fractured rock layer. The engineering pile in the cave geology and the pile forming process have the characteristics of being safe and applicable, and the like, having very good practical and promotional values, and producing good economic benefit after being widely popularized and applied.

The invention relates to the technical field of geological disaster prevention and control, and discloses a karst surface collapse analysis method, which comprises the following steps of obtaining a geological structure, a hydrological structure and a construction collapse condition of a target area; dividing the collapse process of the target area into an engineering construction penetration stage and a sudden collapse stage; in the engineering construction penetration stage, judging the penetration mode of the karst cave or the soil cave in the construction process according to the construction collapse condition; and in the sudden-change collapse stage, obtaining the change condition of the geological structure and the change condition of the hydrological structure, and judging the collapse type of the karst cave or the soil cave so as to determine the surface collapse forming mechanism of the target area. According to the method, the penetration effect analysis of engineering construction is introduced, and the surface collapse formation mechanism of the target area is obtained by combining the change conditions of the geological structure and the hydrological structure, so that the karst surface collapse formation mechanism caused by the penetration effect of engineering construction can be accurately determined, and effective basis and guidance are provided for urban related disaster prevention and reduction work.

Transgenic plants, plant material, and plant cells for synthesis of polyhydroxyalkanoates, preferably poly(3-hydroxybutyrate) (also referred to a as PHB) are provided. Preferred plants that can be genetically engineered to produce PHB include plants that do not normally produce storage products such as oils and carbohydrates, and plants that have a C4 NAD-malic enzyme photosynthetic pathway. Such plants also advantageously produce lignocellulosic biomass that can be converted into biofuels. An exemplary plant that can be genetically engineered to produce PHB and produce lignocellulosic biomass is switchgrass, Panicum virgatum L. A preferred cultivar of switchgrass is Alamo. Other suitable cultivars of switchgrass include but are not limited to Blackwell, Kanlow, Nebraska 28, Pathfinder, Cave-in-Rock, Shelter and Trailblazer.

The invention relates to the technical field of tunnel advance support measure construction, in particular to a construction method for a super-large-section tunnel step of soft rock in a karst cave development stratum. The construction method includes the steps of (1) confirming a surrounding rock grade and a front surrounding rock condition; (2) judging a karst development condition according to the surrounding rock condition, judging whether a karst cave in front of a tunnel arch develops or not according to the karst development condition, and determining advance support measures and design parameters according to the surrounding rock grade and the karst cave development condition; and (3) synchronously excavating upper and lower steps according to step design parameters. Compared with the prior art, the construction method for the super-large-section tunnel step of the soft rock in the karst cave development stratum has the beneficial effects that the step construction method is applied to super-large-section tunnel construction of the karst cave development stratum, and the advance support measures are adopted according to the surrounding rock grade and karst cave development condition classification, so that primary support and karst cave treatment measures are determined according to a tunnel face karst cave exposure condition and a tunnel face state in a geological sketch result, a specific construction mode is adopted for the karst cave development stratum, and the method is targeted and more accurate.

The invention provides a reinforced concrete combined arch bridge spanning karst caves in a tunnel and a construction method thereof. The arch bridge comprises a plurality of profile steel arch ribs arranged in parallel. The two ends of each section steel arch rib are fixedly connected with arch supports poured on the two side walls of the karst cave; a certain distance is reserved between every two adjacent profile steel arch ribs, the adjacent profile steel arch ribs are connected through a plurality of cross beams, supporting steel plates are laid on the cross beams, a concrete arch rib ispoured on the tops of the steel plate supports and the profile steel arch ribs, a concrete filling layer is poured on the top of the concrete arch rib, and the top face of the concrete filling layer is flush with the tunnel bottom face. During construction, firstly, profile steel arch rib installation is completed through vertical rotation construction; then the profile steel arch ribs are used asthe support to construct the upper concrete arch ribs, the characteristics that the profile steel arch rib is small in dead weight, high in strength and convenient and fast to install are fully utilized, formwork supports are prevented from being erected under a bridge, and therefore construction difficulty is lowered, construction quality is guaranteed, safety risks are reduced, and constructioncost is reduced.

The invention discloses a protection structure of a karst cave at the upper part of a tunnel. The protection structure comprises a concrete protection arch, an outer layer protection arch, a concretebuffer layer, a sand buffer layer and a concrete guard wall. The concrete protection arch is tightly adjacent to a tunnel initial support, and the outer contour of the concrete protection arch is thesame as that of the tunnel initial support; the outer layer protection arch is tightly adjacent to the concrete protection arch, and has the same outer contour as the concrete protection arch; the concrete buffer layer is tightly adjacent to the outer layer protection arch, and fills a cavity defined by the outer layer protection arch and the inner wall of the karst cave; the sand buffer layer istightly adjacent to the concrete buffer layer and fills a cavity defined by the top of the concrete buffer layer and the inner wall of the karst cave in the preset height; and the concrete guard wallextends from the bottom of the karst cave to the earth surface on the top of the karst cave along the side wall of the karst cave, and surrounds a tunnel. The protection structure is high in construction efficiency and low in risk in the construction process, can reasonably treat the cavity karst cave at the upper part of the tunnel and enables the structure to be safe and stable, improves the construction quality of the tunnel project, accelerates the construction progress, and ensures the safety in the construction period and the stability in the operation period.

The invention discloses a construction method and structure for a prefabricated tubular pile to penetrate through a karst cave. Force of the prefabricated tubular pile (7) is directly transferred to aforce holding layer (2) at the bottom of the karst cave through a steel pipe (5) penetrating through the karst cave (1). The construction problems that in the process of constructing the prefabricated tubular pile in the karst cave, the prefabricated tubular pile is likely to sink and incline and the bearing capacity at the bottom of the pile does not meet design requirements are effectively solved, the effect of reinforcing a soil body of the karst cave can be effectively achieved, and the bearing capacity requirement of the bottom of the prefabricated tubular pile can be guaranteed. Meanwhile, the construction technology can be used for reinforcing the force holding layer of the pile bottom of the prefabricated tubular pile in the karst cave in a targeted manner, so that the construction period is shortened, the material loss is reduced, the construction cost is reduced, and the national green construction requirement is met.

The invention relates to a karst cave stratum pile foundation structure and a pile forming process, and belongs to the technical field of pile foundation construction. The karst cave stratum pile foundation structure comprises a drill hole formed in a karst cave stratum and a pile casing arranged in the drill hole. The drill hole vertically penetrates through a top plate of a karst cave and a wall body of the karst cave and then extends into a rock mass at the bottom of the karst cave, the length of the pile casing is larger than the height of a cavity of the karst cave, the top end of the pile casing is arranged in the drill hole of the top plate of the karst cave, the bottom end of the pile casing is arranged in the drill hole of the rock mass at the bottom of the karst cave, and concrete is poured into the steel pile casing. The pile casing is arranged in the cavity of the karst cave, the protective wall is formed in the position, in the cavity of the karst cave, of the pile casing, concrete is blocked by the pile casing and is not prone to flowing into the cavity of the karst cave in the concrete pouring process, so that it is guaranteed that the pouring amount of the concrete is consistent with the designed amount, waste of a large amount of concrete caused by the existence of the karst cave is avoided, and the quality of the formed pile foundation is correspondingly improved.

The embodiment of the invention provides a carbonate rock reservoir facture carving volume and dynamic reserve fitting method and device. The method comprises steps: according to seismic data of multiple sample oil wells and a facture carving technology for wave impedance seismic inversion, the seismic carving volume of each sample oil well is acquired; the dynamic reserve of each sample oil wellis acquired; a layer series of a production layer of each sample oil well is determined; and according to the seismic carving volume and the dynamic reserve of a sample oil well corresponding to eachlayer series, a fitting relationship corresponding to each layer series is determined. Thus, the accuracy of the oil well dynamic reserve obtained and determined according to the fitting relationshipis impr4oved.