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With the rapid growth of the oil and gas storage, transportation, and pipeline industries, it is necessary to improve the construction process of oil and gas pipelines. By combining the technical advantages of horizontal directional drilling and pipe jacking construction, the direct pipe laying method is suitable for pipeline crossing in different strata in the oil and gas, water conservancy and hydropower, and municipal industries due to its advantages of less construction land, high speed, and reversibility. Using the rapid jacking and laying of pipelines crossing Nanjuma River in the ‘Jingshihan’ gas pipeline double line project as a case study, this paper investigates the application status of the direct pipe laying method, summarizes the project, and introduces the construction of the working well, equipment selection, guiding control technology, supporting equipment installation, and drag reduction measures, as well as analyzes the influencing factors of thrust force and trajectory deviation combined with formation information.

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Androgenic gland hormone has an insulin-like structure and it is the male-specific hormone found in crustaceans. Androgenic gland hormone controls male sexual differentiation and maintains male sexual characteristics. In this study, the full-length cDNA sequence of the androgenic gland hormone gene in Eriocheir sinensis (EsIAG) was cloned. The total length of the EsIAG cDNA was 1,495 bp, encoding 151 amino acids. EsIAG has the typical conserved structure of other reported IAGs but had low sequence similarity with other crustacean IAGs. EsIAG was expressed specifically in the androgenic gland. Insulin-like growth factor binding protein 7 from the Chinese mitten crab E. sinensis (EsIGFBP7) was highly expressed in the male sex-related organs among nine crab tissues. Interactions between EsIAG and EsIGFBP7 were verified using a yeast-two hybrid assay. These results obtained in this study provide basic information about the regulatory mechanism of male sex differentiation in E. sinensis.